Improve mobile terminal input, selection, and resizing (#1607)

* Improve mobile terminal typing and selection

* Address mobile terminal review feedback

* Remove dead native terminal input branch

* Replay bracketed paste in terminal preamble

* Stop per-key terminal resize claims

* Stabilize terminal resize browser test

* Use tracked terminal mode for native paste

* Restore terminal toolbar focus handling

* Adapt native terminal to active visibility state

* Stabilize native mobile terminal interactions

* Add native terminal fallback boundary

* test(app): expect explicit terminal resize reclaim

* fix(app): stabilize terminal buffer coordinates

* fix(app): restrict terminal resize ownership

* fix(terminal): gate restored input modes

* fix(app): recover stalled terminal WebViews

* chore(app): remove obsolete terminal harnesses

* fix(app): make terminal resize claims explicit

* test(app): stabilize native terminal device flows

* test(app): track absolute scrollback coordinates

* fix(app): isolate terminal WebView streams

* fix(terminal): arbitrate size ownership across clients

The daemon now distinguishes explicit ownership claims from passive geometry updates. This keeps the active client authoritative while allowing its split, viewport, and keyboard changes to resize the PTY without idle clients stealing it.

* test(server): make worker resize assertion portable

Query the worker's authoritative terminal snapshot instead of invoking a Unix-only shell command, so the resize regression exercises the same boundary on Windows and Unix.

docs/terminal-performance.md

@@ -25,6 +25,7 @@ Terminal frames share the daemon main event loop with all agent traffic. The `ev
 - **The input-mode tracker runs once per process boundary, not per hop.** The worker owns the authoritative tracker; the daemon caches the replay preamble from `getTerminalState` responses and `snapshotReady` messages. Do not reintroduce a per-chunk `feed()` on the daemon main loop.
 - **Snapshot catch-up is backpressure-gated.** A stream falls back to a full snapshot only when `outputBytesSinceSnapshot > MAX_TERMINAL_OUTPUT_FRAME_BYTES` (256KB) **and** the client transport reports `bufferedAmount > MAX_CLIENT_BUFFERED_BYTES` (4MB). A client that keeps draining streams continuously, no matter how much output is produced. Before this gate existed, every 256KB of build output dropped a frame and forced a full JSON cell-grid snapshot (~200k objects across IPC) — the historical source of spiky lag and GC hitches.
 - **Client output writes are not serialized per frame.** The emulator runtime drains contiguous plain writes straight into xterm (which buffers internally). Only barrier ops (`clear`, `snapshot`, `suppressInput` writes) wait — behind a zero-length sentinel write — so resets can't interleave with in-flight output.
+- **Terminal size has one daemon-owned claimant.** Focus and direct interaction send a `claim`; later geometry changes from that connection send `update`. A claim transfers ownership even when the dimensions are unchanged, while an update from any other connection is ignored. This lets an owning pane follow splits and keyboard insets without allowing an idle phone or browser to steal the PTY size.
 
 ## Measuring