feat: 角色视觉体系（头像按角色取）+ 时间注入（loop 每轮当前时间）

【角色视觉体系（红线：每个角色自己的头像/背景，绝不串用昔涟）】
- persona.go：Persona 加 Visual{avatar, chatBackground{landscape,portrait}} + DefaultAvatar；每个角色各自配。
- cyrene.yaml：昔涟配 avatar(3F-Q-Happy-1) + chatBackground(横/竖屏)。
- PersonaStore 加 Persona(id)；PersonaSummary 加 avatar/chatBackground；collectPersonas 按角色取
  Persona(id) 视觉（无视觉→空，前端回退默认占位，绝不串角色）。
- 前端：types PersonaRecord 加 avatar/chatBackground；persona.ts personaAvatar(p)=p?.avatar||默认占位
  (殊无昔涟 fallback)；store 加 currentPersona；App 挂载 fetchPersonas 取默认角色；
  TopBar/chat 头像改 personaAvatar(currentPersona)（写死昔涟头像已清除）。

【时间注入（她自然知道现在几点，深夜催睡交给人格/capacity）】
- options.go Options 加 Timezone；loop.go Loop 加 timeLocation/timeZoneName + New 解析 + loadTimezone；
  time.go currentTimeBlock()(当前时间+周几+时区，每轮刷新)；memory.go assembleContext 在「工作记忆」
  前注入时间 system(keyed 在 timeLocation!=nil，无时区不注入不破坏测试)；wire.go Timezone=a.cfg.Timezone。

go build/vet/test 全绿(gateway/loop/persona)；前端 tsc/vite build 75模块绿。红线无写死昔涟头像。

frontend/web/src/components/TopBar.tsx

@@ -2,6 +2,7 @@ import { useState } from "react";
 import { useAppStore } from "../store/useAppStore";
 import { useModeStore } from "../store/useModeStore";
 import { applyTheme, readTheme, type ThemeMode } from "../lib/theme";
+import { personaAvatar } from "../lib/persona";
 import type { Mode, WsStatus } from "../lib/types";
 import { Tag } from "./primitives";
 import { Icon, type IconName } from "./Icon";
@@ -27,6 +28,7 @@ const wsMeta: Record<WsStatus, { label: string; tone: "ok" | "warn" | "neutral"
 export function TopBar(): React.ReactNode {
   const wsStatus = useAppStore((s) => s.wsStatus);
   const mood = useAppStore((s) => s.mood);
+  const currentPersona = useAppStore((s) => s.currentPersona);
   const mode = useModeStore((s) => s.mode);
   const [theme, setTheme] = useState<ThemeMode>(readTheme);
 
@@ -41,7 +43,7 @@ export function TopBar(): React.ReactNode {
   return (
     <header className="glass sticky top-0 z-30 flex h-[var(--mu-topbar-h)] items-center gap-3 border-b border-[var(--mu-glass-border)] px-4">
       <div className="flex items-center gap-2">
-        <img src="/images/Cyrene_Avatar/3rd_Form/Cyrene-3F-Q-Happy-1.png" alt="Cyrene" className="h-7 w-7 rounded-full object-cover" />
+        <img src={personaAvatar(currentPersona)} alt={currentPersona?.name ?? "Cyrene"} className="h-7 w-7 rounded-full object-cover" />
         <div className="leading-tight">
           <div className="text-sm font-semibold">Cyrene · 昔涟</div>
           <div className="text-[11px] text-[var(--mu-text-lo)]">

frontend/web/src/components/chat.tsx

@@ -1,5 +1,7 @@
 import { useState } from "react";
 import type { ChatMessage, Mode, ToolUsed } from "../lib/types";
+import { useAppStore } from "../store/useAppStore";
+import { personaAvatar } from "../lib/persona";
 import { Tag } from "./primitives";
 import { Icon, type IconName } from "./Icon";
 import { WakePath } from "./status";
@@ -130,10 +132,11 @@ function AssistantParaBubble({
   full: boolean;
   active?: boolean;
 }): React.ReactNode {
+  const currentPersona = useAppStore((s) => s.currentPersona);
   return (
     <div className="mu-rise-in flex gap-3">
       {full ? (
-        <img src="/images/Cyrene_Avatar/3rd_Form/Cyrene-3F-Q-Happy-1.png" alt="" className="mt-1 h-7 w-7 shrink-0 rounded-full object-cover" />
+        <img src={personaAvatar(currentPersona)} alt="" className="mt-1 h-7 w-7 shrink-0 rounded-full object-cover" />
       ) : (
         <div className="w-7 shrink-0" aria-hidden />
       )}
@@ -259,9 +262,10 @@ function AssistantBubble({
   mode: Mode;
   active?: boolean;
 }): React.ReactNode {
+  const currentPersona = useAppStore((s) => s.currentPersona);
   return (
     <div className="mu-rise-in flex gap-3">
-      <img src="/images/Cyrene_Avatar/3rd_Form/Cyrene-3F-Q-Happy-1.png" alt="" className="mt-1 h-7 w-7 shrink-0 rounded-full object-cover" />
+      <img src={personaAvatar(currentPersona)} alt="" className="mt-1 h-7 w-7 shrink-0 rounded-full object-cover" />
       <div className="min-w-0 max-w-[85%]">
         <ModeTag mode={mode} />
         {message.mood ? (