v0.50.25: mobile scroll, import timestamps, profile security, mic fallback (#404)

* fix: restore mobile chat scrolling and drawer close (#397)

- static/style.css: add min-height:0 to .layout and .main (flex shrink chain fix for mobile scroll)
- static/style.css: add -webkit-overflow-scrolling:touch, touch-action:pan-y, overscroll-behavior-y:contain to .messages
- static/boot.js: call closeMobileSidebar() on new-conversation button onclick and Ctrl+K shortcut
- tests/test_mobile_layout.py: 41 new lines covering all three CSS fixes and both JS call sites

Original PR by @Jordan-SkyLF

* fix: preserve imported session timestamps (#395)

- api/models.py: add touch_updated_at: bool = True param to Session.save(); import_cli_session() accepts created_at/updated_at kwargs and saves with touch_updated_at=False
- api/routes.py: extract created_at/updated_at from get_cli_sessions() metadata and forward to import_cli_session(); use touch_updated_at=False on post-import save
- tests/test_gateway_sync.py: +53 lines — integration test verifying imported session keeps original timestamp and sorts correctly vs newer sessions; also fix: add WebUI session file cleanup in finally block

Original PR by @Jordan-SkyLF

* fix(profiles): block path traversal in profile switch and delete flows (#399)

Master was vulnerable: switch_profile and delete_profile_api joined user-supplied profile
names directly into filesystem paths with no validation. An attacker could send
'../../etc/passwd' as a profile name to traverse outside the profiles directory.

- api/profiles.py: add _resolve_named_profile_home(name) — validates name with
  ^[a-z0-9][a-z0-9_-]{0,63}$ regex then enforces path containment via
  candidate.resolve().relative_to(profiles_root); use in switch_profile()
- api/profiles.py: add _validate_profile_name() call to delete_profile_api() entry
- api/routes.py: add _validate_profile_name() call at HTTP handler level for
  both /api/profile/switch and /api/profile/delete (fail-fast at API boundary)
- tests/test_profile_path_security.py: 3 tests — traversal rejected, valid name passes

Cherry-picked commit aae7a30 from @Hinotoi-agent (PR was 62 commits behind master)

* feat: add desktop microphone transcription fallback (#396)

Mic button now works in browsers that support getUserMedia/MediaRecorder but
lack SpeechRecognition (e.g. Firefox desktop, some Chromium builds).

- static/boot.js: detect _canRecordAudio (navigator.mediaDevices + getUserMedia + MediaRecorder);
  keep mic button enabled when either SpeechRecognition or MediaRecorder is available;
  MediaRecorder fallback records audio, sends blob to /api/transcribe, inserts transcript
  into the composer; _stopMic() handles all three states (recognition, mediaRecorder, neither)
- api/upload.py: add transcribe_audio() helper — saves uploaded blob to temp file, calls
  transcription_tools.transcribe_audio(), always cleans up temp file
- api/routes.py: add /api/transcribe POST handler — CSRF protected, auth-gated, 20MB limit,
  returns {text:...} or {error:...}
- api/helpers.py: change Permissions-Policy microphone=() to microphone=(self) (required to
  allow getUserMedia in the same origin)
- tests/test_voice_transcribe_endpoint.py: 87 new lines — 3 tests with mocked transcription
- tests/test_sprint19.py: +1 regression guard (microphone=(self) in Permissions-Policy)
- tests/test_sprint20.py: 3 updated tests for new fallback-capability checks

Original PR by @Jordan-SkyLF

* docs: v0.50.25 release — version badge and CHANGELOG

---------

Co-authored-by: Nathan Esquenazi <nesquena@gmail.com>

static/index.html

@@ -535,7 +535,7 @@
                 <div class="settings-section-title">System</div>
                 <div class="settings-section-meta">Instance version and access controls.</div>
               </div>
-              <span class="settings-version-badge">v0.50.24</span>
+              <span class="settings-version-badge">v0.50.25</span>
             </div>
             <div class="settings-field" style="border-top:1px solid var(--border);padding-top:12px;margin-top:8px">
               <label for="settingsPassword" data-i18n="settings_label_password">Access Password</label>