feat(observability): add structured application logging

Emit correlated JSON logs from the API and FunASR services, propagate request IDs to the client, and configure bounded opt-in Docker logging.

Document the host-wide Grafana/Loki query workflow and keep observability deployment ownership outside the application repository.

pages/feedback/index.ts

@@ -1,4 +1,5 @@
 import {
+  copyApiRequestId,
   createFeedbackRecord,
   createVoiceLesson,
   ensureFeedbackSession,
@@ -6,6 +7,7 @@ import {
   generateFeedbackFromVoice,
   getActiveFeedbackSession,
   getApiErrorMessage,
+  getApiRequestId,
   listProfiles,
   markVoiceLessonApplied,
   retryVoiceSegment,
@@ -114,7 +116,8 @@ Page({
     voiceStatus: '语音录入',
     voiceActionable: false,
     primaryActionText: '保存反馈',
-    errorMessage: ''
+    errorMessage: '',
+    errorRequestId: ''
   },
 
   onLoad() {
@@ -189,7 +192,7 @@ Page({
   },
 
   async loadProfiles() {
-    this.setData({ loading: true, errorMessage: '' })
+    this.setData({ loading: true, errorMessage: '', errorRequestId: '' })
     try {
       const profiles = await listProfiles()
       const matchedProfileIndex = profiles.findIndex((profile) => profile.id === this.data.draft.profileId)
@@ -203,7 +206,7 @@ Page({
       })
       await this.loadActiveSession(profileId)
     } catch (error) {
-      this.setData({ errorMessage: getApiErrorMessage(error) })
+      this.setData({ errorMessage: getApiErrorMessage(error), errorRequestId: getApiRequestId(error) })
     } finally {
       this.setData({ loading: false })
     }
@@ -227,7 +230,7 @@ Page({
       this.syncVoicePresentation(session)
       this.scheduleVoicePolling(session)
     } catch (error) {
-      this.setData({ errorMessage: getApiErrorMessage(error) })
+      this.setData({ errorMessage: getApiErrorMessage(error), errorRequestId: getApiRequestId(error) })
     }
   },
 
@@ -309,6 +312,10 @@ Page({
     void this.loadProfiles()
   },
 
+  copyRequestId() {
+    copyApiRequestId(this.data.errorRequestId)
+  },
+
   onProfileChange(event: PickerEvent) {
     this.clearDraftSaveTimer()
     const selectedProfileIndex = Number(event.detail.value)