feat(loop): wire speak tool into the loop (M57)

- speak_tool.go: the speak tool itself — rune-derived timeout budget, structured
  failure codes, persona/emotion stamped on the synthesis ctx, audio persisted
  through the store seam, structured result for the model.
- voice_deps.go: the wiring seam (VoiceSynth / VoiceStore + VoiceStoreFunc
  adapter), voiceEnabled, withSpeakSpec (appended after every schema shrink),
  and captureVoice (success beats failure, last one wins).
- options.go / loop.go: VoiceSynth, VoiceStore, SpeakBudget injection points.
- request.go: advertise speak on both toolSchemas return paths.
- tools.go / tools_invoke.go: carry the batch voice outcome; split invokeOne /
  emitToolExecution / spanStatusForToolPhase / invokeParallel into their own
  file (tools.go was at the 500-line ceiling) and let speak run without a
  dispatcher.
- run.go: keep the voice outcome across tool batches (a later batch without
  speak must not erase it).

Known, deliberate: speak bypasses the capacity allow-set and skill-round
narrowing (it belongs to no built-in toolset), so it is also advertised in
quiet/awake; execution still passes the tool security gate, where speak is not
registered and non-owner actors are denied fail-closed.

internal/runtime/loop/loop.go

@@ -143,7 +143,13 @@ type Loop struct {
 	// 逐字节一致。它由装配期一次性挂上，之后只读；每会话的状态在 SkillFace 内部
 	// 按会话分桶并自带锁，因此循环的并发 Run 契约不变。
 	skillFace *SkillFace
-	log       *slog.Logger
+	// voiceSynth / voiceStore 是 speak 的注入依赖（M57）。两者都非 nil 时
+	// 循环向模型广告 speak 并自行承载它的执行（见 voice_deps.go）；
+	// speakBudget 是超时预算的替换公式，nil 用内置公式。
+	voiceSynth  VoiceSynth
+	voiceStore  VoiceStore
+	speakBudget func(int) int
+	log         *slog.Logger
 }
 
 // New 由 opts 构建 Loop 并应用默认值。MaxRounds 非正时
@@ -216,6 +222,9 @@ func New(opts Options) *Loop {
 		imageResolver:       opts.Vision,
 		documentResolver:    opts.DocumentResolver,
 		documentInjectChars: docInjectChars,
+		voiceSynth:          opts.VoiceSynth,
+		voiceStore:          opts.VoiceStore,
+		speakBudget:         opts.SpeakBudget,
 		log:                 sourcedLog(opts.Log),
 	}
 }