fix(tui): honor display.busy_input_mode in TUI v2 (#17110)

* fix(tui): honor display.busy_input_mode in TUI v2

The TUI v2 frontend hard-coded `composerActions.enqueue(full)` whenever
`ui.busy` was true. The classic CLI and gateway adapters honor the
`display.busy_input_mode` config key (`interrupt` | `queue` | `steer`),
but Ink ignored it — sending a message during a long-running turn always
landed in the queue regardless of config. The config default is already
`interrupt` (hermes_cli/config.py), so users who explicitly opted into
that experience were silently stuck on the legacy queue path.

This wires the value through the existing config-sync surface:

* `applyDisplay` now reads `display.busy_input_mode`, defaults to
  `interrupt` (matching `_load_busy_input_mode` in tui_gateway), and
  drops it into a new `UiState.busyInputMode` field.
* `dispatchSubmission` and the queue-edit fall-through call a shared
  `handleBusyInput` helper that branches on the mode:
    * `queue`     — legacy behavior, append to the queue.
    * `steer`     — call `session.steer`; on rejection, fall back to
                    queue with a sys note.
    * `interrupt` — `turnController.interruptTurn(...)` then `send()`,
                    so the new prompt actually moves.
* Mtime polling in `useConfigSync` already re-applies `config.full`, so
  flipping `display.busy_input_mode` in `~/.hermes/config.yaml` takes
  effect on the next 5s tick without restarting the TUI.

Tests:
* `applyDisplay → busy_input_mode` covers normalization + UiState fan-out.
* `normalizeBusyInputMode` mirrors the Python side's allow-list.

Validation:
* `npm run type-check` (in `ui-tui/`) — clean.
* `npm test --run` (in `ui-tui/`) — 394/394.

* review(copilot): narrow busy_input_mode type, preserve queue order on steer fallback

* review(copilot): clarify handleBusyInput comment (option, not return value)

* fix(tui): default busy_input_mode to queue in TUI (CLI keeps interrupt)

In a full-screen TUI users typically author the next prompt while the
agent is still streaming, so an unintended interrupt loses in-flight
typing.  TUI fallback now defaults to `queue`; CLI / messaging
adapters keep `interrupt` as the framework default.

Override per-config via `display.busy_input_mode: interrupt` (or
`steer`) — the normalize/wire path is unchanged, only the missing-
value branch differs from the Python default.

uiStore initial value also flipped to `queue` so first-frame render
before `config.full` lands matches the eventual normalized value.

ui-tui/src/app/useConfigSync.ts

@@ -10,7 +10,7 @@ import type {
 } from '../gatewayTypes.js'
 import { asRpcResult } from '../lib/rpc.js'
 
-import type { StatusBarMode } from './interfaces.js'
+import type { BusyInputMode, StatusBarMode } from './interfaces.js'
 import { turnController } from './turnController.js'
 import { patchUiState } from './uiStore.js'
 
@@ -24,6 +24,27 @@ const STATUSBAR_ALIAS: Record<string, StatusBarMode> = {
 export const normalizeStatusBar = (raw: unknown): StatusBarMode =>
   raw === false ? 'off' : typeof raw === 'string' ? (STATUSBAR_ALIAS[raw.trim().toLowerCase()] ?? 'top') : 'top'
 
+const BUSY_MODES = new Set<BusyInputMode>(['interrupt', 'queue', 'steer'])
+
+// TUI defaults to `queue` even though the framework default
+// (`hermes_cli/config.py`) is `interrupt`.  Rationale: in a full-screen
+// TUI you're typically authoring the next prompt while the agent is
+// still streaming, and an unintended interrupt loses work.  Set
+// `display.busy_input_mode: interrupt` (or `steer`) explicitly to
+// opt out per-config; CLI / messaging adapters keep their `interrupt`
+// default unchanged.
+const TUI_BUSY_DEFAULT: BusyInputMode = 'queue'
+
+export const normalizeBusyInputMode = (raw: unknown): BusyInputMode => {
+  if (typeof raw !== 'string') {
+    return TUI_BUSY_DEFAULT
+  }
+
+  const v = raw.trim().toLowerCase() as BusyInputMode
+
+  return BUSY_MODES.has(v) ? v : TUI_BUSY_DEFAULT
+}
+
 const MTIME_POLL_MS = 5000
 
 const quietRpc = async <T extends Record<string, any> = Record<string, any>>(
@@ -43,6 +64,7 @@ export const applyDisplay = (cfg: ConfigFullResponse | null, setBell: (v: boolea
 
   setBell(!!d.bell_on_complete)
   patchUiState({
+    busyInputMode: normalizeBusyInputMode(d.busy_input_mode),
     compact: !!d.tui_compact,
     detailsMode: resolveDetailsMode(d),
     detailsModeCommandOverride: false,