feat: phase 3 + phase 4 complete — v0.4.0

Phase 3:
- Config reload via SIGHUP (handle_signals loop: .hup reloads config, .int/.term shutdown)
- Hot reload: cfg, webhook_routes, ntfy client, dedup updated without restart

Phase 4:
- Silence rules: POST /api/silence?duration=30m, GET /api/silence, DELETE /api/silence
- Grouping: buffer 10s, events grouped with (×N in 10s) suffix
- CI/CD: .gitea/workflows/ci.yml (build + test on push/PR)

Docs:
- ROADMAP.md: phases 3 & 4 marked DONE, version table updated
- ARCHITECTURE.md: synced with actual code

Version: 0.1.0 → 0.4.0 (main.v, v.mod)

.gitea/workflows/ci.yml

@@ -0,0 +1,27 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    container:
+      image: thevlang/vlang:alpine
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Build
+        run: v -prod .
+
+      - name: Test
+        run: v test .
+
+      - name: Verify version
+        run: |
+          ./ntfy-bridge --version
+          ./ntfy-bridge --help