Add QR pairing (terminal QR, in-app scanner, iris://pair deep link)

docs/10-android-app.md

@@ -115,7 +115,7 @@ app/shared/src/
 
 - `ToolCard` renders `tool.start/progress/end` frames.
 - The gateway always supplies the **full** tool data: it forces
-  `display.platforms.android.tool_progress: verbose` (so the progress line
+  `display.platforms.iris.tool_progress: verbose` (so the progress line
   carries the full args JSON → `tool.start.args`) and captures each completed
   call via the `post_tool_call` hook (→ `tool.end` `output_preview` /
   `duration` / `ok`). The app decides how much to show.
@@ -317,5 +317,13 @@ Storage: `AndroidSqliteDriver` (app database dir) on Android,
 - First launch → **Connect**: server URL + token (or scan QR). "Test connection"
   does a real `hello` (not just a TCP probe — per hermes desktop guidance, the
   auth leg must be exercised). On success → save (secure storage) → main.
+- **Scan QR** (Android only, `docs/20`): a button below the token field opens
+  `QrScanActivity` (CameraX + ML Kit, on-device, no Play services), requests the
+  `CAMERA` permission, and pre-fills URL + token from the decoded
+  `iris://pair…` payload via `PairLink.parse`. It never auto-connects — the
+  user still taps "Test & Connect". A non-pairing QR sets an error and leaves
+  the fields untouched. The same payload also arrives as an `iris://pair` deep
+  link (system scanner / other phones) and pre-fills the screen the same way.
+  Hidden on desktop (no camera).
 - States: connecting / connected / reconnecting / degraded / auth-failed — each
   with honest copy and a way out.