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)

main.v

@@ -3,7 +3,7 @@ module main
 import os
 import flag
 
-const version = '0.1.0'
+const version = '0.4.0'
 const author  = 'Bruno Charest'
 
 fn main() {
@@ -52,7 +52,7 @@ fn main() {
 		print_startup_info(cfg)
 	}
 
-	mut app := new_app(cfg, quiet)
+	mut app := new_app(cfg, config_path, quiet)
 	app.run() or {
 		eprintln('Server error: ${err}')
 		exit(1)