feat(asr): 本地语音转写接入为一级路由 + 并行工作流合并提交

按用户指示做**一包提交**，不按工作流拆分。本提交刻意混合了多条并行线：

  · 本地 ASR 接管：audio 成为与 chat/embed/image/video 同等的路由类别
    （IsLocalRoute 单一判据、audio 健康探测、default_audio_route、
    auto 占位、GET /api/ai/routes/audio、回退云端时界面明示「音频已出网」）
  · LLM 调用层：ctx 贯穿、ToolCall/ToolSchema、EmptyCompletionError /
    TransientUpstreamError（按错误类型而非文案判重试）
  · 编排 Agent：general_assistant orchestrate/persistence/spec_driver
  · 联网搜索：internal/search（playwright）
  · 网盘：backend + 前端
  · 前端 UI：导航/路由/工作台若干页
  · 交付文档：DELIVERY.md / AR04 / 部署文档的「无 Python」表述据实改写，
    新增 eai_agentplatform-asr.service、asr.env、clonezilla-cleanup 清 ~/asr-poc

不分拆的原因：dev 早期，粒度不该打断工作节奏。且实测过——这些改动
**在编译上是同一个单元**（llm.go 的 ctx 签名变更牵动 12 个调用点，
chat_message.go 的 ctx 改动又与编排重写同处一个 hunk），拆出来的中间态编不过。
详见 TOP_CODING_RULES.md G14.5 与 bugs_and_errors.md E09。

Co-Authored-By: Claude Code <noreply@anthropic.com>

deploy/searxng/docker-compose.yml

@@ -0,0 +1,33 @@
+services:
+  # 使用 host 网络：容器与宿主机共享网络栈。
+  # 原因：本机环境 Docker bridge 模式的 NAT 出站被阻断，容器无法访问外网；
+  # host 模式下 searxng 直接复用宿主网络可正常联网（已验证 python host-net 连 baidu:443 OK）。
+  searxng-valkey:
+    image: ${SEARXNG_VALKEY_IMAGE:-ghcr.io/valkey-io/valkey:8.1.4}
+    container_name: eai-searxng-valkey
+    command: ["valkey-server", "--save", "", "--appendonly", "no"]
+    restart: unless-stopped
+    network_mode: host
+    volumes:
+      - searxng-valkey-data:/data
+
+  searxng:
+    image: ${SEARXNG_IMAGE:-ghcr.io/searxng/searxng:latest}
+    container_name: eai-searxng
+    restart: unless-stopped
+    network_mode: host
+    environment:
+      SEARXNG_BASE_URL: ${SEARXNG_PUBLIC_BASE_URL:-http://127.0.0.1:18080/}
+      SEARXNG_SECRET: ${SEARXNG_SECRET:-eai-agentplatform-searxng-change-me}
+      SEARXNG_VALKEY_URL: valkey://127.0.0.1:6379/0
+      SEARXNG_PORT: ${SEARXNG_PORT:-18080}
+      UWSGI_THREADS: 4
+    volumes:
+      - ./searxng:/etc/searxng:ro
+      - searxng-cache:/var/cache/searxng
+    depends_on:
+      - searxng-valkey
+
+volumes:
+  searxng-cache:
+  searxng-valkey-data:

deploy/searxng/searxng/settings.yml

@@ -0,0 +1,47 @@
+# SearXNG settings for pj0235 eai_agentplatform
+use_default_settings:
+  engines:
+    keep_only:
+      - baidu
+      - 360search
+      - sogou
+      - bing
+      - wikipedia
+      - bilibili
+
+general:
+  debug: false
+  instance_name: "pj0235 SearXNG"
+
+search:
+  safe_search: 0
+  autocomplete: ""
+  formats:
+    - html
+    - json
+
+server:
+  secret_key: "eai-agentplatform-searxng-change-me"
+  limiter: false
+  image_proxy: true
+
+valkey:
+  url: valkey://127.0.0.1:6379/0
+
+engines:
+  - name: baidu
+    disabled: false
+    timeout: 5.0
+  - name: 360search
+    disabled: false
+    timeout: 5.0
+  - name: sogou
+    disabled: false
+    timeout: 6.0
+  - name: bing
+    disabled: false
+    timeout: 5.0
+  - name: wikipedia
+    disabled: false
+  - name: bilibili
+    disabled: false