fix: per-event delete button, Docker network default, polling interval duration parsing

- Add per-event delete button (trash icon on hover) in event log entries
- Set Docker network default to 'docker-watcher' in DB schema + migration for existing DBs
- Parse Go duration strings (5m, 1h) to seconds in settings UI, convert back on save
- Clear error when network is empty in deployer instead of hidden fallback

internal/deployer/deployer.go

@@ -286,6 +286,9 @@ func (d *Deployer) executeDeploy(
 	d.logDeploy(deployID, "Image pulled successfully", "info")
 
 	// Step 2: Ensure network exists.
+	if settings.Network == "" {
+		return containerID, proxyRouteID, instanceID, fmt.Errorf("docker network not configured in settings")
+	}
 	networkID, err := d.docker.EnsureNetwork(ctx, settings.Network)
 	if err != nil {
 		return containerID, proxyRouteID, instanceID, fmt.Errorf("ensure network: %w", err)

internal/store/store.go

@@ -109,6 +109,8 @@ func (s *Store) runMigrations() error {
 		`ALTER TABLE settings ADD COLUMN traefik_cert_resolver TEXT NOT NULL DEFAULT 'letsencrypt'`,
 		`ALTER TABLE settings ADD COLUMN traefik_network TEXT NOT NULL DEFAULT ''`,
 		`ALTER TABLE settings ADD COLUMN traefik_api_url TEXT NOT NULL DEFAULT ''`,
+		// Set default network for existing databases with empty network.
+		`UPDATE settings SET network = 'docker-watcher' WHERE network = ''`,
 	}
 
 	for _, m := range migrations {
@@ -198,7 +200,7 @@ CREATE TABLE IF NOT EXISTS settings (
 	id                  INTEGER PRIMARY KEY CHECK (id = 1),
 	domain              TEXT NOT NULL DEFAULT '',
 	server_ip           TEXT NOT NULL DEFAULT '',
-	network             TEXT NOT NULL DEFAULT '',
+	network             TEXT NOT NULL DEFAULT 'docker-watcher',
 	subdomain_pattern   TEXT NOT NULL DEFAULT 'stage-{stage}-{project}',
 	notification_url    TEXT NOT NULL DEFAULT '',
 	npm_url             TEXT NOT NULL DEFAULT '',