Integrate JailJS for CSP-restricted execution in browser extension

Major changes:
- Migrate browser-extension to use web-ui package (85% code reduction)
- Add JailJS content script with ES6+ transform support
- Expose DOM constructors (Event, KeyboardEvent, etc.) to JailJS
- Support top-level await by wrapping code in async IIFE
- Add returnFile() support in JailJS execution
- Refactor KeyStore into pluggable storage-adapter pattern
- Make ChatPanel configurable with sandboxUrlProvider and additionalTools
- Update jailjs to 0.1.1

Files deleted (33 duplicate files):
- All browser-extension components, dialogs, state, tools, utils
- Now using web-ui versions via @mariozechner/pi-web-ui

Files added:
- packages/browser-extension/src/content.ts (JailJS content script)
- packages/web-ui/src/state/storage-adapter.ts
- packages/web-ui/src/state/key-store.ts

Browser extension now has only 5 source files (down from 38).

packages/web-ui/src/state/storage-adapter.ts

@@ -0,0 +1,77 @@
+/**
+ * Generic storage adapter interface for key/value persistence
+ */
+export interface StorageAdapter {
+	get(key: string): Promise<string | null>;
+	set(key: string, value: string): Promise<void>;
+	remove(key: string): Promise<void>;
+	getAll(): Promise<Record<string, string>>;
+}
+
+/**
+ * LocalStorage implementation
+ */
+export class LocalStorageAdapter implements StorageAdapter {
+	async get(key: string): Promise<string | null> {
+		return localStorage.getItem(key);
+	}
+
+	async set(key: string, value: string): Promise<void> {
+		localStorage.setItem(key, value);
+	}
+
+	async remove(key: string): Promise<void> {
+		localStorage.removeItem(key);
+	}
+
+	async getAll(): Promise<Record<string, string>> {
+		const result: Record<string, string> = {};
+		for (let i = 0; i < localStorage.length; i++) {
+			const key = localStorage.key(i);
+			if (key) {
+				const value = localStorage.getItem(key);
+				if (value) result[key] = value;
+			}
+		}
+		return result;
+	}
+}
+
+/**
+ * Chrome/Firefox extension storage implementation
+ */
+export class ChromeStorageAdapter implements StorageAdapter {
+	private readonly storage: any;
+
+	constructor() {
+		const isBrowser = typeof globalThis !== "undefined";
+		const hasChrome = isBrowser && (globalThis as any).chrome?.storage;
+		const hasBrowser = isBrowser && (globalThis as any).browser?.storage;
+
+		if (hasBrowser) {
+			this.storage = (globalThis as any).browser.storage.local;
+		} else if (hasChrome) {
+			this.storage = (globalThis as any).chrome.storage.local;
+		} else {
+			throw new Error("Chrome/Browser storage not available");
+		}
+	}
+
+	async get(key: string): Promise<string | null> {
+		const result = await this.storage.get(key);
+		return result[key] || null;
+	}
+
+	async set(key: string, value: string): Promise<void> {
+		await this.storage.set({ [key]: value });
+	}
+
+	async remove(key: string): Promise<void> {
+		await this.storage.remove(key);
+	}
+
+	async getAll(): Promise<Record<string, string>> {
+		const result = await this.storage.get();
+		return result || {};
+	}
+}