fix(command): add missing command handler wiring and lint fixes

Wire SetCommandHandler into ChannelInboundProcessor so slash commands
are intercepted before reaching the LLM. Also apply lint fixes across
command package (strconv.Itoa, comment formatting, unused code removal)
and remove obsolete tool-call-browser.vue component.

internal/command/handler.go

@@ -49,17 +49,17 @@ type Handler struct {
 	mcpConnService  *mcp.ConnectionService
 	inboxService    *inbox.Service
 
-	modelsService    *models.Service
-	providersService *providers.Service
-	memProvService   *memprovider.Service
-	searchProvService *searchproviders.Service
-	browserCtxService *browsercontexts.Service
-	emailService      *emailpkg.Service
+	modelsService      *models.Service
+	providersService   *providers.Service
+	memProvService     *memprovider.Service
+	searchProvService  *searchproviders.Service
+	browserCtxService  *browsercontexts.Service
+	emailService       *emailpkg.Service
 	emailOutboxService *emailpkg.OutboxService
-	heartbeatService  *heartbeat.Service
-	queries           *dbsqlc.Queries
-	skillLoader       SkillLoader
-	containerFS       ContainerFS
+	heartbeatService   *heartbeat.Service
+	queries            *dbsqlc.Queries
+	skillLoader        SkillLoader
+	containerFS        ContainerFS
 
 	logger *slog.Logger
 }