feat(ext): handcraft the whole ext from scratch

AI coding doesn't work for MV3 extensions.
Threading was an unfixable mess.
Removed everything and rebuilt by hand.

packages/extension/src/entrypoints/background.ts

@@ -1,114 +1,44 @@
-/**
- * Background Script (Service Worker) - Stateless Message Relay
- *
- * Completely stateless. Only two responsibilities:
- * 1. Relay AGENT_TO_PAGE messages from SidePanel to ContentScript
- * 2. Broadcast TAB_CHANGE events to all extension pages
- */
-import {
-	type AgentToPageMessage,
-	type TabChangeMessage,
-	isExtensionMessage,
-} from '../agent/protocol'
+import { handlePageControlMessage } from '@/agent/RemotePageController.background'
+import { handleTabControlMessage } from '@/agent/TabsController.background'
 
-// ============================================================================
-// Message Relay
-// ============================================================================
+function handleUtilsMessage(
+	message: { type: 'UTILS'; action: string; payload: any },
+	sender: chrome.runtime.MessageSender,
+	sendResponse: (response: unknown) => void
+): boolean {
+	const { action, payload } = message
 
-chrome.runtime.onMessage.addListener(
-	(
-		message: unknown,
-		_sender: chrome.runtime.MessageSender,
-		sendResponse: (response?: unknown) => void
-	): boolean => {
-		if (!isExtensionMessage(message)) {
+	switch (action) {
+		case 'get_tab_info': {
+			chrome.tabs
+				.get(payload.tabId)
+				.then((tab) => {
+					const result = { title: tab.title || '', url: tab.url || '' }
+					sendResponse(result)
+				})
+				.catch((error) => {
+					sendResponse({ error: error instanceof Error ? error.message : String(error) })
+				})
+			return true // async response
+		}
+
+		default:
+			sendResponse({ error: `Unknown TAB_CONTROL action: ${action}` })
 			return false
-		}
-
-		if (message.type === 'AGENT_TO_PAGE') {
-			handleAgentToPage(message as AgentToPageMessage, sendResponse)
-			return true // Async response
-		}
+	}
+}
 
+chrome.runtime.onMessage.addListener((message, sender, sendResponse) => {
+	if (message.type === 'TAB_CONTROL') {
+		return handleTabControlMessage(message, sender, sendResponse)
+	} else if (message.type === 'PAGE_CONTROL') {
+		return handlePageControlMessage(message, sender, sendResponse)
+	} else if (message.type !== 'UTILS') {
+		return handleUtilsMessage(message, sender, sendResponse)
+	} else {
+		sendResponse({ error: 'Unknown message type' })
 		return false
 	}
-)
-
-/**
- * Forward RPC call from SidePanel to ContentScript
- */
-async function handleAgentToPage(
-	msg: AgentToPageMessage,
-	sendResponse: (response: { success: boolean; result?: unknown; error?: string }) => void
-): Promise<void> {
-	const { tabId, method, args } = msg
-
-	try {
-		// Forward directly to content script, same message format
-		const result = await chrome.tabs.sendMessage(tabId, msg)
-		sendResponse({ success: true, result })
-	} catch (error) {
-		sendResponse({
-			success: false,
-			error: error instanceof Error ? error.message : String(error),
-		})
-	}
-}
-
-// ============================================================================
-// Tab Event Broadcasting
-// ============================================================================
-
-function broadcastTabChange(message: TabChangeMessage): void {
-	chrome.runtime.sendMessage(message).catch(() => {
-		// No listeners (sidepanel not open)
-	})
-}
-
-chrome.tabs.onRemoved.addListener((tabId) => {
-	broadcastTabChange({
-		type: 'TAB_CHANGE',
-		eventType: 'removed',
-		tabId,
-	})
-})
-
-chrome.tabs.onUpdated.addListener((tabId, changeInfo) => {
-	if (!changeInfo.status) return
-
-	broadcastTabChange({
-		type: 'TAB_CHANGE',
-		eventType: 'updated',
-		tabId,
-		data: {
-			status: changeInfo.status,
-			url: changeInfo.url,
-		},
-	})
-})
-
-chrome.tabs.onActivated.addListener((activeInfo) => {
-	broadcastTabChange({
-		type: 'TAB_CHANGE',
-		eventType: 'activated',
-		tabId: activeInfo.tabId,
-		data: {
-			windowId: activeInfo.windowId,
-		},
-	})
-})
-
-chrome.windows.onFocusChanged.addListener((windowId) => {
-	const focused = windowId !== chrome.windows.WINDOW_ID_NONE
-	broadcastTabChange({
-		type: 'TAB_CHANGE',
-		eventType: 'windowFocusChanged',
-		tabId: -1,
-		data: {
-			windowId: focused ? windowId : undefined,
-			focused,
-		},
-	})
 })
 
 // ============================================================================