feat: v6.2.0 Web Clipper — extension navigateur (capture article/selection/bookmark/screenshot)

- Service app/services/web_clipper.py: sanitize HTML, html->blocks, extraction article, creation page workspace-aware, rate limit 50/h, device registration
- Router app/routers/web_clipper.py: POST /api/v2/web-clipper/clip, GET /status, POST /auth/verify, GET/DELETE /devices, GET /extensions (download page), auth via session ou Bearer (api_tokens / extension_devices)
- Migration 19: extension_devices + extension_clips (+ indexes)
- Extension Manifest V3: content.js (floating button, selection), background.js (clip + contextMenus), popup.html/js, clipper.css, icons
- Settings UI: onglet Extensions (liste devices, revoke, test clip, liens download), page /extensions
- Tests: 16 tests web_clipper (sanitize, blocks, article/bookmark/selection/screenshot, bearer, rate-limit, devices, extensions page)
- Bump version 6.1.0 -> 6.2.0

static/extension/manifest.json

@@ -0,0 +1,40 @@
+{
+  "manifest_version": 3,
+  "name": "FlowDeck Web Clipper",
+  "description": "Capturez du contenu web directement dans FlowDeck",
+  "version": "1.0.0",
+  "permissions": ["activeTab", "storage", "scripting", "contextMenus"],
+  "host_permissions": ["<all_urls>", "https://flowdeck.local/*", "https://flowdeck.dracodev.net/*", "http://localhost:8080/*", "http://localhost:3000/*"],
+  "background": {
+    "service_worker": "background.js"
+  },
+  "action": {
+    "default_popup": "popup.html",
+    "default_icon": {
+      "16": "icons/icon-16.png",
+      "32": "icons/icon-32.png",
+      "48": "icons/icon-48.png",
+      "128": "icons/icon-128.png"
+    }
+  },
+  "content_scripts": [
+    {
+      "matches": ["<all_urls>"],
+      "js": ["content.js"],
+      "css": ["clipper.css"],
+      "run_at": "document_idle"
+    }
+  ],
+  "web_accessible_resources": [
+    {
+      "resources": ["readability.js"],
+      "matches": ["<all_urls>"]
+    }
+  ],
+  "icons": {
+    "16": "icons/icon-16.png",
+    "32": "icons/icon-32.png",
+    "48": "icons/icon-48.png",
+    "128": "icons/icon-128.png"
+  }
+}