diff --git a/.github/workflows/release-guard.yml b/.github/workflows/release-guard.yml
index af53ab6..5669e01 100644
--- a/.github/workflows/release-guard.yml
+++ b/.github/workflows/release-guard.yml
@@ -84,3 +84,11 @@ jobs:
         run: python3 packaging/check_workflows_yaml.py --self-test
       - name: workflow 全部可被真 YAML 解析器 parse（无裸控制字符）
         run: python3 packaging/check_workflows_yaml.py
+      # M190 r3：`update-test-key` 是**信任锚的开关**（把公开的测试公钥并进信任表）。它只许由
+      # `crates/presenter` 的 `[dev-dependencies]` 打开；进了发布构建就等于「谁都能签出官方更新」。
+      # 判据：core 的 `Cargo.toml` 只许自己的声明、presenter 只许 `[dev-dependencies]` 段内、
+      # 其余（workflow / packaging 脚本 / 根 Cargo.toml / cargo 配置）出现即红。
+      - name: 测试公钥守门自检（注入 workflow / dependencies / 根 Cargo.toml 三处变异）
+        run: python3 packaging/check_test_key_off.py --self-test
+      - name: 测试公钥不进发布构建（只许 presenter 的 dev-dependencies）
+        run: python3 packaging/check_test_key_off.py
diff --git a/Cargo.lock b/Cargo.lock
index 694148f..18d3b5d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -5209,6 +5209,7 @@ dependencies = [
 name = "unlucky-presenter"
 version = "0.2.3"
 dependencies = [
+ "ed25519-dalek",
  "serde",
  "serde_json",
  "unlucky-core",
diff --git a/crates/core/Cargo.toml b/crates/core/Cargo.toml
index d11d56a..aef07b1 100644
--- a/crates/core/Cargo.toml
+++ b/crates/core/Cargo.toml
@@ -81,3 +81,10 @@ workspace = true
 # 验收用法见 `crates/cli/tests/update_e2e_test.rs` 的文件头；`packaging/check_test_source_off.py`
 # 守门「发布流水线与打包脚本都不许打开它」。
 update-test-source = []
+
+# M190：把**测试公钥**并进信任表（`trust::TEST_ONLY`）。它只加一把**公开**的钥，**不**开任何数据源
+# 开关（没有环境变量、没有 `DirSource`）。唯一使用者是 `crates/presenter` 的 `[dev-dependencies]`：
+# presenter 的更新链路用例要构造「本构建认得」的签名清单，而它们编译 core 时既没有 `cfg(test)`，
+# 也不该去打开 `update-test-source`（那条同时给出「本地目录当更新源」这条路）。
+# 守门：`packaging/check_test_key_off.py`（只许出现在这里与 presenter 的 dev-dependencies）。
+update-test-key = []
diff --git a/crates/core/src/update/trust.rs b/crates/core/src/update/trust.rs
index 4ab3af3..b7e5ca2 100644
--- a/crates/core/src/update/trust.rs
+++ b/crates/core/src/update/trust.rs
@@ -70,11 +70,26 @@ pub(crate) const TEST_ONLY: &[PinnedKey] = &[PinnedKey {
 }];
 
 /// 本构建实际的信任锚（正式表 + 仅测试构建才有的那把测试钥）。
+///
+/// 三档「仅测试」的口径，逐档说明为什么需要它：
+///
+/// | 档 | 谁在用 | 为什么不能只靠 `cfg(test)` |
+/// |---|---|---|
+/// | `cfg(test)` | core 自己的单测 | 够用 |
+/// | `update-test-source` | CLI 的端到端验收（`--features update-test-source`） | 那是**另一个 target**，`cfg(test)` 不生效 |
+/// | `update-test-key` | `crates/presenter` 的 `[dev-dependencies]` | presenter 的更新链路用例编译 core 时既无 `cfg(test)`，也不该打开 `update-test-source`（那条会同时给出「本地目录当更新源」这条路）。这一档**只**加一把公开的测试公钥，不开任何数据源开关 |
+///
+/// 三者都进不了发布产物：`PRODUCTION` 之外没有任何路径能把 `TEST_ONLY` 带进 `--release` 构建
+/// （官方构建三个 feature 都不开，且 `check_test_source_off.py` / `check_test_key_off.py` 守着）。
 pub(crate) fn keyring() -> &'static [PinnedKey] {
     static ALL: OnceLock<Vec<PinnedKey>> = OnceLock::new();
     ALL.get_or_init(|| {
         let mut keys = PRODUCTION.to_vec();
-        if cfg!(any(test, feature = "update-test-source")) {
+        if cfg!(any(
+            test,
+            feature = "update-test-source",
+            feature = "update-test-key"
+        )) {
             keys.extend_from_slice(TEST_ONLY);
         }
         keys
diff --git a/crates/presenter/Cargo.toml b/crates/presenter/Cargo.toml
index 55d6914..5412fa6 100644
--- a/crates/presenter/Cargo.toml
+++ b/crates/presenter/Cargo.toml
@@ -34,3 +34,12 @@ workspace = true
 # （`-p` 认 package 名 `unlucky-app-iced`；`unlucky-launcher-iced` 是 bin 名，写 `-p` 会找不到包）。
 # 官方发布构建不带这个 feature（`packaging/check_test_source_off.py` 守门）。
 update-test-source = ["unlucky-core/update-test-source"]
+
+[dev-dependencies]
+# M190：presenter 的**更新链路用例**要构造「本构建认得」的签名清单（真发布必须带
+# `manifest.json.sig`，没有它 core 一律拒装）。这里打开 core 的 `update-test-key`：它**只**把一把
+# **公开**的测试公钥并进信任表，不开任何数据源开关（与 `update-test-source` 是两件事）。
+# 只出现在 `[dev-dependencies]`：库/发布构建拿不到它。守门：`packaging/check_test_key_off.py`。
+unlucky-core = { path = "../core", features = ["update-test-key"] }
+# 夹具用同一套种子现签清单（与 `crates/core/src/update/tests/support_sign.rs` 同源）。
+ed25519-dalek.workspace = true
diff --git a/crates/presenter/src/host/update_tests.rs b/crates/presenter/src/host/update_tests.rs
index a0d3a69..58057d5 100644
--- a/crates/presenter/src/host/update_tests.rs
+++ b/crates/presenter/src/host/update_tests.rs
@@ -88,9 +88,48 @@ fn manifest_for(version: &str, payload: &[u8], notes: &str) -> String {
     )
 }
 
-/// 造一个本地更新源目录（`dist/stable.json` + `dist/asset.exe`）。
-fn dir_source(tmp: &TempDir, manifest: &str, payload: &[u8]) {
+/// 测试签名钥的 32 字节种子。
+///
+/// **与 `crates/core/src/update/tests/support_sign.rs` 同源**（同一个种子、同一个 `key_id`、
+/// 同一个信封形状）：那边是 core 单测的夹具，这里是 presenter 侧的**等价薄夹具**——presenter 不能
+/// 依赖 core 的 `#[cfg(test)]` 资产，也不该把测试资产导出成生产 API。改一处就要改两处；
+/// 对不上时用例会以「签名验不过 / 不认识的钥」红，而不是静默变绿。
+const TEST_SIGNING_SEED: &[u8; 32] = b"ull-m190-test-key-seed-000000001";
+/// 测试钥的 `key_id`（与 `crates/core/src/update/trust.rs::TEST_ONLY` 一致）。
+const TEST_KEY_ID: &str = "test-only-key";
+
+/// 用测试钥给清单签一份 `manifest.sig` 信封（M190 的信封形状：多签名数组 + 冗余摘要）。
+///
+/// 只有 `[dev-dependencies]` 打开了 core 的 `update-test-key`，所以这把公开的测试公钥在**测试构建**
+/// 的信任表里；发布构建里没有它，也就装不了用公开种子签出来的清单。
+fn signature_envelope(manifest: &str) -> String {
+    use ed25519_dalek::{Signer, SigningKey};
+    let signature = SigningKey::from_bytes(TEST_SIGNING_SEED)
+        .sign(manifest.as_bytes())
+        .to_bytes();
+    let hex: String = signature.iter().map(|byte| format!("{byte:02x}")).collect();
+    let digest = sha256(manifest.as_bytes());
+    format!(
+        r#"{{"format":1,"signatures":[{{"alg":"ed25519","key_id":"{TEST_KEY_ID}","sig":"{hex}","manifest_sha256":"{digest}"}}]}}"#
+    )
+}
+
+/// 写一份清单**连它的签名**（`dist/stable.json` + `dist/stable.json.sig`）。
+///
+/// 真发布必须带 `.sig`（core 的 `verified_manifest` 先验签再解析），所以夹具一律成对落盘；
+/// 「坏清单」「空清单」这些用例也照签——它们要证的是「签名对、内容坏/为空」时的行为，
+/// 而不是绕过签名。
+fn write_manifest(tmp: &TempDir, manifest: &str) {
     tmp.write("dist/stable.json", manifest.as_bytes());
+    tmp.write(
+        "dist/stable.json.sig",
+        signature_envelope(manifest).as_bytes(),
+    );
+}
+
+/// 造一个本地更新源目录（`dist/stable.json` + 它的签名 + `dist/asset.exe`）。
+fn dir_source(tmp: &TempDir, manifest: &str, payload: &[u8]) {
+    write_manifest(tmp, manifest);
     tmp.write("dist/asset.exe", payload);
 }
 
@@ -180,7 +219,7 @@ fn a_broken_manifest_degrades_to_failure_not_up_to_date() {
         ("bad version", manifest_for("not-a-version", b"abc", "")),
     ] {
         let tmp = TempDir::new("badmanifest");
-        tmp.write("dist/stable.json", manifest.as_bytes());
+        write_manifest(&tmp, &manifest);
         let outcome = outcome_of(job(&tmp).check(&version("0.2.2"), Channel::Stable));
         assert!(
             matches!(outcome, UpdateOutcome::Failed(_)),
@@ -206,7 +245,7 @@ fn an_empty_manifest_means_nothing_published_yet() {
         r#"{"channel":"stable","releases":[]}"#.to_string(),
     ] {
         let tmp = TempDir::new("empty-manifest");
-        tmp.write("dist/stable.json", manifest.as_bytes());
+        write_manifest(&tmp, &manifest);
         let outcome = outcome_of(job(&tmp).check(&version("0.2.2"), Channel::Stable));
         assert!(
             matches!(&outcome, UpdateOutcome::UpToDate { latest: None }),
@@ -219,15 +258,14 @@ fn an_empty_manifest_means_nothing_published_yet() {
 #[test]
 fn a_higher_version_without_our_platform_is_not_up_to_date() {
     let tmp = TempDir::new("missing-artifact");
-    tmp.write(
-        "dist/stable.json",
-        format!(
+    write_manifest(
+        &tmp,
+        &format!(
             r#"{{"channel":"stable","releases":[{{"version":"0.9.0","channel":"stable","artifacts":[{{"target":"{}","format":"portable-exe","url":"asset.exe","size":3,"sha256":"{}"}}]}}]}}"#,
             // 故意给一个不可能匹配本机的目标（`unknown` 架构永远对不上）
             "linux-x86",
             sha256(b"abc")
-        )
-        .as_bytes(),
+        ),
     );
     let outcome = outcome_of(job(&tmp).check(&version("0.2.2"), Channel::Stable));
     assert!(
diff --git a/packaging/check_test_key_off.py b/packaging/check_test_key_off.py
new file mode 100644
index 0000000..c36a23c
--- /dev/null
+++ b/packaging/check_test_key_off.py
@@ -0,0 +1,238 @@
+#!/usr/bin/env python3
+"""守 `update-test-key`：这把**公开**的测试公钥不许进发布构建（M190 r3）。
+
+背景：`crates/core` 的信任表（`trust::PRODUCTION`）正式构建里是空的（fail-closed，等用户录钥），
+测试公钥 `trust::TEST_ONLY` 只在三档「仅测试」构建里并入：`cfg(test)`、测试通道那条 feature、
+`update-test-key`。第三档是给 `crates/presenter` 的 `[dev-dependencies]` 用的——presenter 的更新链路
+用例要构造「本构建认得」的签名清单，而它编译 core 时既没有 `cfg(test)`，也不该打开
+「测试通道」那条 feature（它会**同时**给出「本地目录当更新源」这条路，是另一个更大的口子；
+那条由 `check_test_source_off.py` 守。⚠ 本文件**刻意不写那条 feature 的全名**：那个守门按字面
+扫 `packaging/**`，写了这里就红——这是它的设计（宁可误杀也不放过），不是笔误）。
+
+这一档比「测试通道」那条 feature 窄，但它仍然是**信任锚的开关**：一旦进发布构建，任何人都能用公开种子
+签出「官方更新」。所以它的出现位置必须是**白名单**，而不是「没人会这么写」：
+
+| 允许出现的地方 | 形态 |
+|---|---|
+| `crates/core/Cargo.toml` | 只能是它自己的声明 `update-test-key = [` |
+| `crates/presenter/Cargo.toml` | 只能出现在 `[dev-dependencies]` 段内 |
+| 本脚本 | 它必须写出这个 feature 名 |
+
+其余任何地方（workflow、`packaging/` 的脚本、根 `Cargo.toml`、`.cargo/config*.toml`、presenter 的
+`[dependencies]`）提到它即红。`--self-test` 把这三类真实回归各注入一次，并断言合法写法不误杀。
+
+    python3 packaging/check_test_key_off.py
+    python3 packaging/check_test_key_off.py --self-test
+"""
+
+from __future__ import annotations
+
+import argparse
+import re
+import sys
+import tempfile
+from pathlib import Path
+
+FEATURE = "update-test-key"
+ROOT = Path(__file__).resolve().parent.parent
+GUARD = Path(__file__).resolve()
+
+#: 扫描面（逐项列举，不用 `**` 全仓：那会把 `target/` 拖进来）。
+GLOBS = (
+    ".github/workflows/**/*.yml",
+    ".github/workflows/**/*.yaml",
+    ".github/actions/**/*.yml",
+    ".github/actions/**/*.yaml",
+    "packaging/**/*.py",
+    "packaging/**/*.sh",
+    "packaging/**/*.ps1",
+    "Cargo.toml",
+    "crates/*/Cargo.toml",
+    "Makefile",
+    "justfile",
+    "Justfile",
+    "Taskfile.yml",
+    "Taskfile.yaml",
+    "crates/*/Makefile",
+    "packaging/Makefile",
+    ".cargo/config.toml",
+    ".cargo/config",
+    "crates/*/.cargo/config.toml",
+    "crates/*/.cargo/config",
+)
+
+#: 白名单：(相对路径, 允许的形态)。形态见 `check_manifest` 的三种判法。
+ALLOWED_DECLARATION = "crates/core/Cargo.toml"
+ALLOWED_DEV_DEPENDENCY = "crates/presenter/Cargo.toml"
+
+DECLARATION = re.compile(rf"^\s*{re.escape(FEATURE)}\s*=\s*\[")
+SECTION = re.compile(r"^\s*\[([^\]]+)\]\s*$")
+
+
+def strip_comment(line: str) -> str:
+    """引号感知地剥注释（与 `check_test_source_off.py` 同一手法，省得两处对同一行有不同看法）。"""
+    quote = None
+    for index, char in enumerate(line):
+        if quote is not None:
+            if char == quote:
+                quote = None
+        elif char in "\"'":
+            quote = char
+        elif char == "#" and (index == 0 or line[index - 1].isspace()):
+            return line[:index]
+    return line
+
+
+def check_manifest(path: Path, where: str) -> list[str]:
+    """`Cargo.toml`：核心只许自己的声明；presenter 只许 `[dev-dependencies]` 段内。"""
+    problems: list[str] = []
+    section = ""
+    for number, line in enumerate(path.read_text(encoding="utf-8").splitlines(), start=1):
+        code = strip_comment(line).strip()
+        if not code:
+            continue
+        header = SECTION.match(code)
+        if header:
+            section = header.group(1).strip()
+            continue
+        if FEATURE not in code:
+            continue
+        if where == ALLOWED_DECLARATION and DECLARATION.match(code):
+            continue
+        if where == ALLOWED_DEV_DEPENDENCY and section == "dev-dependencies":
+            continue
+        problems.append(
+            f"::error file={where}:{number}::{where} 在 `[{section or '顶部'}]` 里写了 `{FEATURE}`；"
+            "它只许出现在 crates/core/Cargo.toml 自己的声明与 crates/presenter/Cargo.toml 的 "
+            "`[dev-dependencies]` 里（这把公钥进发布构建 = 谁都能签出「官方更新」）"
+        )
+    return problems
+
+
+def check_plain(path: Path, where: str) -> list[str]:
+    """其余文件类型：出现即红（不解释形态）。"""
+    problems: list[str] = []
+    for number, line in enumerate(path.read_text(encoding="utf-8").splitlines(), start=1):
+        if FEATURE in strip_comment(line):
+            problems.append(
+                f"::error file={where}:{number}::{where} 提到 `{FEATURE}`：它不进 workflow / 打包脚本 / "
+                "cargo 配置（测试钥只许由 crates/presenter 的 dev-dependencies 打开）"
+            )
+    return problems
+
+
+def scan(root: Path) -> list[str]:
+    """扫整个仓库，返回所有问题（空 = 绿）。"""
+    problems: list[str] = []
+    for pattern in GLOBS:
+        for path in sorted(root.glob(pattern)):
+            if not path.is_file() or path.resolve() == GUARD:
+                continue
+            where = path.relative_to(root).as_posix()
+            try:
+                if path.name == "Cargo.toml":
+                    problems += check_manifest(path, where)
+                else:
+                    problems += check_plain(path, where)
+            except (OSError, UnicodeDecodeError) as error:
+                problems.append(f"::error file={where}::读不到：{error}")
+    return problems
+
+
+# ────────────────────────── 变异自测 ──────────────────────────
+
+BASELINE = {
+    "crates/core/Cargo.toml": (
+        "[features]\nother-feature = []\n\n# 注释里提到 update-test-key 不算违规\ntest-key = []\n"
+        "update-test-key = []\n"
+    ),
+    "crates/presenter/Cargo.toml": (
+        "[dependencies]\nunlucky-core = { path = \"../core\" }\n\n"
+        "[dev-dependencies]\nunlucky-core = { path = \"../core\", features = [\"update-test-key\"] }\n"
+    ),
+    ".github/workflows/ci.yml": "jobs:\n  a:\n    steps:\n      - run: cargo test\n",
+}
+
+VECTORS = [
+    (
+        "workflow 里打开它",
+        {".github/workflows/ci.yml": "jobs:\n  a:\n    steps:\n      - run: cargo build --features update-test-key\n"},
+        "red",
+    ),
+    (
+        "presenter 的 [dependencies] 里打开它",
+        {
+            "crates/presenter/Cargo.toml": (
+                "[dependencies]\nunlucky-core = { path = \"../core\", features = [\"update-test-key\"] }\n"
+            )
+        },
+        "red",
+    ),
+    (
+        "根 Cargo.toml 把依赖提起来",
+        {
+            "Cargo.toml": (
+                '[workspace.dependencies]\nunlucky-core = { path = "crates/core", '
+                'features = ["update-test-key"] }\n'
+            )
+        },
+        "red",
+    ),
+    ("打包脚本提到它", {"packaging/x.sh": "cargo build --features update-test-key\n"}, "red"),
+    (
+        "core 自己的声明（合法）",
+        {"crates/core/Cargo.toml": "[features]\nupdate-test-key = []\n"},
+        "green",
+    ),
+    ("注释里提到它（合法）", {"packaging/y.py": "# 见 update-test-key 的说明\n"}, "green"),
+]
+
+
+def _scan_case(files: dict[str, str]) -> list[str]:
+    with tempfile.TemporaryDirectory(prefix="ull-test-key-guard-") as temp:
+        root = Path(temp)
+        for relative, text in files.items():
+            path = root / relative
+            path.parent.mkdir(parents=True, exist_ok=True)
+            path.write_text(text, encoding="utf-8")
+        return scan(root)
+
+
+def self_test() -> int:
+    failures = 0
+    baseline = _scan_case(BASELINE)
+    if baseline:
+        print(f"FAIL 基线被判红：{baseline}", file=sys.stderr)
+        failures += 1
+    for label, files, expect in VECTORS:
+        merged = dict(BASELINE)
+        merged.update(files)
+        problems = _scan_case(merged)
+        red = bool(problems)
+        if (expect == "red") != red:
+            print(f"FAIL 向量「{label}」期望 {expect}，实际 {'red' if red else 'green'}", file=sys.stderr)
+            failures += 1
+    print(f"self-test: {'ok' if failures == 0 else f'{failures} 处失败'}（{len(VECTORS)} 条向量 + 基线）")
+    return 0 if failures == 0 else 1
+
+
+def main(argv: list[str] | None = None) -> int:
+    parser = argparse.ArgumentParser(description="测试公钥不许进发布构建（M190）")
+    parser.add_argument("--self-test", action="store_true", help="注入变异：该红的红、该绿的绿")
+    parser.add_argument("--dir", type=Path, default=ROOT, help="仓库根（默认本文件上一级）")
+    args = parser.parse_args(argv)
+
+    if args.self_test:
+        return self_test()
+    problems = scan(args.dir)
+    for line in problems:
+        print(line, file=sys.stderr)
+    if problems:
+        print(f"FAIL：{len(problems)} 处（`{FEATURE}` 只许由 crates/presenter 的 dev-dependencies 打开）", file=sys.stderr)
+        return 1
+    print(f"ok: `{FEATURE}` 只出现在允许的位置（core 的声明 + presenter 的 dev-dependencies）")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())