feat(share): "Biz Connect" in the iOS share sheet — share a photo/file into a chat

Adds the reverse direction: share FROM Photos/Files/Safari INTO a Biz Connect
conversation. An app can only appear in the iOS share sheet as an app-extension
target, so this is real native work, not a web change.

Pieces:
- mobile/ios-share/ShareViewController.swift: a UI-less Share Extension. It stages
  the shared items into the App Group container and opens bizconnect://share. It
  deliberately does NOT reimplement the chat picker — that lives in the app, which
  already has the chat list, search and upload progress. Appends to the manifest
  (never overwrites), so sharing twice before opening the app loses nothing.
- mobile/scripts/add-share-extension.rb: injects the extension target into the
  Capacitor-generated Xcode project on every CI build (Codemagic checks out fresh),
  using the xcodeproj gem that ships with CocoaPods. Embeds it, sets the bundle id
  <app>.share, and MERGES the App Group into the app's entitlements rather than
  clobbering them (push's aps-environment must survive). Idempotent.
- mobile/plugins/share-inbox: getPending()/clear() to read that manifest — the App
  Group container isn't one of Filesystem's known directories, so it needs a bridge.
- home.html: on bizconnect://share (and every resume, and cold-launch), read the
  inbox and show a "Send to…" picker over the chat list; chosen files run the SAME
  upload + /api/messages send as an in-app attachment. Reuses convertFileSrc to read
  the staged bytes with no base64 marshalling.
- ios-patch.sh registers the bizconnect URL scheme; codemagic.yaml fetches a profile
  for the .share bundle id too.

One-time manual gate (CI cannot toggle App capabilities): the App Group
group.com.bizgaze.connect must be created and enabled on both App IDs in the Apple
portal — documented in mobile/IOS_SETUP.md. Without it the two processes can't see
each other's files and sharing silently no-ops; everything else still works.

Validated cross-file: pod-name/jsName/method wiring for all three plugins, App
Group id identical in all 4 files, URL scheme consistent across extension/plist/web,
entitlement-merge preserves push. Needs a new iOS build (new targets + plugins).

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

mobile/IOS_SETUP.md

@@ -89,3 +89,29 @@ listing yet — see the follow-up below (you can still *view* a screen someone e
 - Mobile **web** can't switch the audio output route (`setSinkId` is unimplemented on iOS/Android), so the
   in-meeting speaker/earpiece/Bluetooth control is web-only where it works and hidden where it doesn't.
 - True routing on iOS needs a small native plugin driving `AVAudioSession`. Phase-2 native task.
+
+---
+
+## Share Extension ("Biz Connect" in the iOS share sheet) — one-time Apple portal setup
+
+The app now has a **Share Extension** target (`com.bizgaze.connect.share`) so users can share a photo /
+video / file FROM the Photos or Files app INTO a Biz Connect conversation. The Codemagic build injects the
+target and fetches a profile for it automatically, but two things can ONLY be done once, by hand, in the
+Apple Developer portal — CI cannot toggle App capabilities:
+
+1. **Create the App Group** (developer.apple.com → Identifiers → App Groups → +):
+   identifier **`group.com.bizgaze.connect`**.
+2. **Enable the App Groups capability on BOTH App IDs** and assign them to that group:
+   - `com.bizgaze.connect` (the app)
+   - `com.bizgaze.connect.share` (the extension — create this App ID if the first build hasn't yet;
+     `fetch-signing-files --create` will register it, then edit it to add App Groups)
+   After enabling the capability, the provisioning profiles must be regenerated — the next Codemagic build
+   does that via `fetch-signing-files`, so just re-run it once the capability is on.
+
+If the App Group isn't set up, the app and the extension can't see each other's files: sharing will appear
+to do nothing (the extension stages the file, but the app finds an empty inbox). Everything else — download
+to the Files folder, the Photos "Connect" album, Manage storage — works without it.
+
+Also enabled by this change (main app Info.plist, done automatically by `ios-patch.sh`):
+- `UIFileSharingEnabled` + `LSSupportsOpeningDocumentsInPlace` → the **Biz Connect** folder in Files.
+- `CFBundleURLTypes` scheme **`bizconnect`** → lets the extension bounce back into the app after staging.