feat(chat): rich shared-media view, status selector, drag-drop upload + fixes

Chat / shared media:
- Media/Docs/Links: clean underline tabs (green active), audio & video now
  classified as Media and rendered as tiles (download + headphone/play +
  duration) instead of broken-image glyphs; image thumbnails -> lightbox
- Drag-and-drop a file/video/image onto a conversation to send it
- Fix: removed #chatPanel{position:relative} override that collapsed the
  conversation pane (messages spilled into a clipped right-edge strip)
- "Media, links & docs" row cleaned up (no folder/placeholder icon); media
  popup keeps the back arrow, drops the redundant close button

Presence / status:
- Single current-status row with an arrow that expands Available/Away/On leave
- On leave = circle with minus, In a call = solid red indicators
- Fix: selected-status tick now follows the chosen option

Icons: added headphones + play; bumped icons.js cache-bust to v4

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

server/public/manifest.json

@@ -1,5 +1,5 @@
 {
-  "name": "BizGaze Connect",
+  "name": "Biz Connect",
   "short_name": "Connect",
   "description": "Chat, screen share, and video meetings for the BizGaze ecosystem.",
   "start_url": "/home",