huge refacto of the permissions handling + fix various regression

/**
 * Keeps permissionsStore aligned with the browser. The store is a cache,
 * never a second source of truth: every signal re-reads the browser via
 * syncPermissions() (single writer).
 *
 * Re-sync triggers, all event-driven — no polling:
 *  - devicechange: granting permission reveals device labels/ids, so this
 *    fires on grant in every browser INCLUDING Safari — replacing the
 *    previous 500ms Safari polling. (A denial is caught by the concurrent
 *    getUserMedia rejection → notePermissionDeniedFromGum.)
 *  - window focus: returning from the browser/system permission UI.
 *  - Permissions API 'change' events, where the query is supported.
 */

src/frontend/package-lock.json

@@ -22,7 +22,6 @@
         "@tanstack/react-query": "5.101.1",
         "@timephy/rnnoise-wasm": "1.0.0",
         "crisp-sdk-web": "1.1.2",
-        "derive-valtio": "0.2.0",
         "hoofd": "1.7.3",
         "humanize-duration": "3.33.2",
         "i18next": "26.3.1",
@@ -4710,15 +4709,6 @@
         "node": ">= 0.8"
       }
     },
-    "node_modules/derive-valtio": {
-      "version": "0.2.0",
-      "resolved": "https://registry.npmjs.org/derive-valtio/-/derive-valtio-0.2.0.tgz",
-      "integrity": "sha512-6slhaFHtfaL3t5dLYaQt6s4G2xZymhu0Ktdl7OMeVk8+46RgR8ft6FL0Tr4F31W+yPH03nJe1SSP4JFy2hSMRA==",
-      "license": "MIT",
-      "peerDependencies": {
-        "valtio": ">=2.0.0-rc.0"
-      }
-    },
     "node_modules/detect-libc": {
       "version": "2.1.2",
       "resolved": "https://registry.npmjs.org/detect-libc/-/detect-libc-2.1.2.tgz",