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>

codemagic.yaml

@@ -53,6 +53,14 @@ workflows:
         script: |
           bash mobile/scripts/ios-patch.sh
 
+      - name: Add the Share Extension target
+        script: |
+          # Inject the second target (Biz Connect in the iOS share sheet) into the freshly-generated
+          # Xcode project. Uses the `xcodeproj` gem that ships with CocoaPods, so no extra install.
+          # Runs BEFORE pod install: the extension uses no pods, and this way the workspace that pods
+          # generates already contains the new target.
+          ruby mobile/scripts/add-share-extension.rb
+
       - name: Set up code signing
         script: |
           # Create the distribution certificate + provisioning profile from the ASC API key and add the
@@ -65,11 +73,21 @@ workflows:
           # cert it has no key for ("Cannot save Signing Certificates without certificate private key").
           # By passing our own fixed private key (CERTIFICATE_PRIVATE_KEY, a secure var in the
           # `ios_signing` group), the cert is created once from that key and reused by every build.
+          #
+          # TWO bundle ids now need signing: the app AND the share extension (<app>.share). Each gets its
+          # own App Store profile. The App Group capability (group.com.bizgaze.connect) must be enabled on
+          # BOTH App IDs in the Apple Developer portal — see mobile/IOS_SETUP.md. fetch-signing-files
+          # registers a missing bundle id and creates its profile, but does NOT toggle the App Group
+          # capability, so that stays a one-time manual step.
           keychain initialize
           app-store-connect fetch-signing-files "$BUNDLE_ID" \
             --type IOS_APP_STORE \
             --certificate-key="@env:CERTIFICATE_PRIVATE_KEY" \
             --create
+          app-store-connect fetch-signing-files "${BUNDLE_ID}.share" \
+            --type IOS_APP_STORE \
+            --certificate-key="@env:CERTIFICATE_PRIVATE_KEY" \
+            --create
           keychain add-certificates
 
       - name: Install CocoaPods