Add GamepadAPI, WebGL readPixels noise, auto-prune, import/export, badge

New fingerprint vectors:
- Gamepad API: getGamepads() returns empty (prevents controller fingerprinting)
- WebGL readPixels: seeded pixel noise on framebuffer reads

New features:
- Auto-prune: configurable automatic removal of inactive containers
- Import/export: backup and restore all settings from options page
- Toolbar badge: shows active container count
- CHANGELOG.md: version history

Bumped to v0.5.0 with 20 spoofed fingerprint vectors.

CHANGELOG.md

@@ -0,0 +1,46 @@
+# Changelog
+
+## 0.5.0
+
+- Gamepad API spoofing (returns empty, prevents controller fingerprinting)
+- WebGL readPixels noise (seeded pixel noise on framebuffer reads)
+- Auto-prune: automatically remove inactive containers after configurable days
+- Import/export all settings (seeds, whitelist, vector config) from options page
+- Active container count badge on toolbar icon
+- Updated test page with new vector sections
+
+## 0.4.1
+
+- Skip all fingerprint overrides on Google auth domains to fix login rejection
+- Keep auth redirects in originating container for session isolation
+- Skip User-Agent spoofing on accounts.google.com and accounts.youtube.com
+
+## 0.4.0
+
+- Added 6 new fingerprint vectors: Font API (document.fonts), DOM element dimensions, HTTP header spoofing (User-Agent, Accept-Language, Client Hints), Speech Synthesis, Performance Timing, Storage Estimate
+- WebGL parameter normalization (MAX_TEXTURE_SIZE, MAX_VERTEX_ATTRIBS, etc.)
+- Font enumeration hardening via offsetWidth/Height noise
+- Total spoofed vectors: 18
+
+## 0.3.0
+
+- HTTP header spoofing: User-Agent and Accept-Language modified per container
+- Client Hints header stripping (Sec-CH-UA, Sec-CH-UA-Platform)
+- Speech synthesis protection (getVoices returns empty)
+- matchMedia screen dimension override
+- Performance.now() precision reduction
+- navigator.storage.estimate() spoofing
+
+## 0.2.0
+
+- Coherent device profiles with 3 archetypes (Windows, Linux, macOS)
+- User-Agent spoofing with matching platform, oscpu, appVersion
+- Added data_collection_permissions for AMO submission
+
+## 0.1.0
+
+- Initial release
+- Per-site container isolation with automatic domain detection
+- 12 fingerprint vectors: Canvas, WebGL, Audio, Navigator, Screen, Timezone, WebRTC, Fonts, ClientRects, Plugins, Battery, Connection
+- Popup UI with per-container toggle, regenerate, prune, reset
+- Options page with vector toggles, domain whitelist, container management