feat(cicd): #46c OTEL Tracing 遷移到 Gitea workflows

- CD: awoooi-cd service (192.168.0.188:24318)
- E2E: awoooi-e2e service
- 環境變數: OTEL_EXPORTER_OTLP_ENDPOINT, OTEL_SERVICE_NAME, OTEL_RESOURCE_ATTRIBUTES

原 GitHub workflows (cd7d63e) → Gitea workflows (ADR-039)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.gitea/workflows/cd.yaml

@@ -23,6 +23,10 @@ env:
   HARBOR: 192.168.0.110:5000
   # Harbor Proxy Cache (指向 DockerHub 的內部 Mirror，避免拉取限額)
   HARBOR_MIRROR: 192.168.0.110:5001
+  # OTEL CI/CD 監控 (2026-03-31 #46c - 遷移到 Gitea)
+  OTEL_EXPORTER_OTLP_ENDPOINT: http://192.168.0.188:24318
+  OTEL_SERVICE_NAME: awoooi-cd
+  OTEL_RESOURCE_ATTRIBUTES: service.version=${{ github.sha }},deployment.environment=production
 
 jobs:
   build-and-deploy:

.gitea/workflows/e2e-health.yaml

@@ -14,6 +14,12 @@ on:
   schedule:
     - cron: '0 16 * * *'  # 每日 00:00 台北 (UTC+8)
 
+# OTEL CI/CD 監控 (2026-03-31 #46c)
+env:
+  OTEL_EXPORTER_OTLP_ENDPOINT: http://192.168.0.188:24318
+  OTEL_SERVICE_NAME: awoooi-e2e
+  OTEL_RESOURCE_ATTRIBUTES: deployment.environment=production
+
 jobs:
   e2e-health:
     runs-on: ubuntu-latest

apps/api/src/main.py

@@ -26,7 +26,8 @@ import sentry_sdk
 import structlog
 from fastapi import FastAPI, Request
 from fastapi.middleware.cors import CORSMiddleware
-from fastapi.responses import JSONResponse
+from fastapi.responses import JSONResponse, Response
+from prometheus_client import CONTENT_TYPE_LATEST, generate_latest
 from sentry_sdk.integrations.fastapi import FastApiIntegration
 from sentry_sdk.integrations.starlette import StarletteIntegration
 
@@ -437,6 +438,21 @@ app.include_router(
 )
 
 
+# =============================================================================
+# Prometheus Metrics Endpoint
+# =============================================================================
+# 2026-03-31 ogt: 暴露 Prometheus 指標供告警系統使用
+
+
+@app.get("/metrics", include_in_schema=False)
+async def prometheus_metrics() -> Response:
+    """Prometheus metrics endpoint for alerting"""
+    return Response(
+        content=generate_latest(),
+        media_type=CONTENT_TYPE_LATEST,
+    )
+
+
 # =============================================================================
 # Root Endpoint
 # =============================================================================