Add webhook logging, pagination, middleware, migrations, and prod hardening

- Webhook event logging repo and subscription webhook idempotency
- Pagination helper (echohelpers) with cursor/offset support
- Request ID and structured logging middleware
- Push client improvements (FCM HTTP v1, better error handling)
- Task model version column, business constraint migrations, targeted indexes
- Expanded categorization chain tests
- Email service and config hardening
- CI workflow updates, .gitignore additions, .env.example updates

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.claude/settings.local.json

@@ -2,7 +2,17 @@
   "permissions": {
     "allow": [
       "WebSearch",
-      "WebFetch(domain:github.com)"
+      "WebFetch(domain:github.com)",
+      "Bash(go build:*)",
+      "Bash(go test:*)",
+      "Bash(docker compose:*)",
+      "Bash(go vet:*)",
+      "Bash(head:*)",
+      "Bash(docker exec:*)",
+      "Bash(git add:*)",
+      "Bash(docker ps:*)",
+      "Bash(git commit:*)",
+      "Bash(git push:*)"
     ]
   },
   "enableAllProjectMcpServers": true,