opentui(v6): post-rebase fixups — dedup probe mouse, .demo lint ignore, cap tests to windowing-aware contract

Rebasing onto fcf49f313 (multi-click selection) collided in the test
probe (both sides added 'mouse' — deduped) and surfaced two test debts
the cap-restore commit (3cc56517a) had shipped masked by a piped exit
code: store cap tests still asserted the 1000 default (now: 3000
windowed, 1000 with HERMES_TUI_WINDOWING=0, both covered), and the
burst-interplay test relied on the old cap trimming a 1500-row burst
(now pins HERMES_TUI_MAX_MESSAGES=1000 explicitly for both stores).
Also: .demo/ build artifacts excluded from typed linting. 669 tests
exit 0 (verified unpiped). Multi-click selections flow through the
same renderer selection seam, so windowing's drag-freeze + row-pinning
covers them with no changes.

ui-opentui/eslint.config.mjs

@@ -4,9 +4,9 @@ import unusedImports from "eslint-plugin-unused-imports"
 
 export default tseslint.config(
   {
-    // .bench/ is a build artifact of the bench suite's `nodes` cell
-    // (bench/run.mjs builds scripts/mem-bench.tsx into it) — never lint it.
-    ignores: ["node_modules/**", "dist/**", ".bench/**", ".repos/**", "*.frame.txt", "*.ansi"],
+    // .bench/ and .demo/ are build artifacts (bench `nodes` cell and the
+    // smoke demo: `node scripts/build.mjs scripts/demo.tsx .demo`) — never lint.
+    ignores: ["node_modules/**", "dist/**", ".bench/**", ".demo/**", ".repos/**", "*.frame.txt", "*.ansi"],
   },
   js.configs.recommended,
   ...tseslint.configs.recommendedTypeChecked,

ui-opentui/src/test/lib/render.ts

@@ -65,8 +65,6 @@ export interface RenderProbe {
   readonly scroll: (x: number, y: number, direction: 'up' | 'down') => Promise<void>
   /** The mock keyboard (typeText / pressArrow / pressEnter / …) — pair with `settle()`. */
   readonly keys: TestRendererSetup['mockInput']
-  /** The full mock mouse (drag / pressDown / release / …) — selection tests. */
-  readonly mouse: TestRendererSetup['mockMouse']
   /** The live test renderer (e.g. `getSelection()` assertions). */
   readonly renderer: TestRendererSetup['renderer']
   /** Run a render pass + flush so simulated input lands in the next `frame()`. */
@@ -125,7 +123,6 @@ export async function renderProbe(
       await setup.flush()
     },
     keys: setup.mockInput,
-    mouse: setup.mockMouse,
     renderer: setup.renderer,
     settle: async () => {
       await setup.renderOnce()

ui-opentui/src/test/store.test.ts

@@ -506,10 +506,14 @@ describe('session store — resume hydrate (Phase 4b)', () => {
 
 describe('session store — rolling message cap (bounds the Yoga node high-water mark)', () => {
   const ENV_KEY = 'HERMES_TUI_MAX_MESSAGES'
+  const WINDOWING_KEY = 'HERMES_TUI_WINDOWING'
   const prev = process.env[ENV_KEY]
+  const prevWindowing = process.env[WINDOWING_KEY]
   afterEach(() => {
     if (prev === undefined) delete process.env[ENV_KEY]
     else process.env[ENV_KEY] = prev
+    if (prevWindowing === undefined) delete process.env[WINDOWING_KEY]
+    else process.env[WINDOWING_KEY] = prevWindowing
   })
 
   test('caps the message array at the env-tuned MESSAGE_CAP, dropping the oldest (head)', () => {
@@ -578,23 +582,37 @@ describe('session store — rolling message cap (bounds the Yoga node high-water
     expect(store.state.messages.at(-1)!.text).toBe('h7')
   })
 
-  test('defaults to 1000 (the handle-safe ceiling) when the env var is unset/invalid', () => {
+  test('defaults to 3000 (windowed ceiling) when the env var is unset/invalid and windowing is on', () => {
+    // With transcript windowing (the default) the mounted set is ~3 viewports
+    // regardless of store size, so the scrollback ceiling is 3000 (#27 payoff).
     delete process.env[ENV_KEY]
+    delete process.env[WINDOWING_KEY]
     const store = createSessionStore()
-    for (let i = 0; i < 1050; i++) store.pushUser(`m${i}`)
-    expect(store.state.messages).toHaveLength(1000)
+    for (let i = 0; i < 3050; i++) store.pushUser(`m${i}`)
+    expect(store.state.messages).toHaveLength(3000)
     expect(store.state.messages[0]!.text).toBe('m50') // oldest 50 dropped
   })
 
-  test('env values ABOVE the handle-safe ceiling are clamped to it (the native handle table binds, not memory)', () => {
+  test('HERMES_TUI_WINDOWING=0 keeps the handle-safe 1000 ceiling (every row mounts again)', () => {
+    delete process.env[ENV_KEY]
+    process.env[WINDOWING_KEY] = '0'
+    const store = createSessionStore()
+    for (let i = 0; i < 1050; i++) store.pushUser(`m${i}`)
+    expect(store.state.messages).toHaveLength(1000)
+    expect(store.state.messages[0]!.text).toBe('m50')
+  })
+
+  test('env values ABOVE the ceiling are clamped to it (the native handle table binds, not memory)', () => {
     // @opentui/core's global handle registry holds 65,534 live objects and a
     // text renderable costs 3; ~47 handles/row on the realistic fixture means
-    // ≳1,400 live rows crashes mid-mount ("Failed to create SyntaxStyle").
-    // A 100000 "cap" is therefore a crash sentence, not a cap — clamp it.
+    // ≳1,400 live MOUNTED rows crashes mid-mount ("Failed to create
+    // SyntaxStyle"). Windowing bounds the mounted set (peak 31 measured), so
+    // the windowed ceiling is 3000 stored rows; a 100000 "cap" still clamps.
     process.env[ENV_KEY] = '100000'
+    delete process.env[WINDOWING_KEY]
     const store = createSessionStore()
-    for (let i = 0; i < 1100; i++) store.pushUser(`m${i}`)
-    expect(store.state.messages).toHaveLength(1000)
+    for (let i = 0; i < 3100; i++) store.pushUser(`m${i}`)
+    expect(store.state.messages).toHaveLength(3000)
     expect(store.state.dropped).toBe(100)
     expect(store.state.messages[0]!.text).toBe('m100')
   })

ui-opentui/src/test/transcriptWindow.test.tsx

@@ -153,7 +153,18 @@ function clipScrollbar(frame: string): string {
 
 describe('transcript windowing — S2 append-time adjudication', () => {
   test('bursting 1500 appends keeps the peak mounted-row count bounded (< 120)', async () => {
-    const onStore = createSessionStore()
+    // Pin the cap below the burst size: this test ALSO exercises the
+    // cap-trim × windowing interplay (trimmed rows' spacers must be pruned,
+    // scroll-to-top must land on the oldest SURVIVOR, row-500). The default
+    // ceiling is 3000 under windowing (#27) — a 1500-row burst never trims it.
+    process.env.HERMES_TUI_MAX_MESSAGES = '1000'
+    const onStore = (() => {
+      try {
+        return createSessionStore()
+      } finally {
+        delete process.env.HERMES_TUI_MAX_MESSAGES
+      }
+    })()
     onStore.apply({ type: 'gateway.ready' })
     const on = await mountTranscript(onStore, '1')
     try {
@@ -172,7 +183,14 @@ describe('transcript windowing — S2 append-time adjudication', () => {
       // ZERO-JANK INVARIANT survives the burst: spacers (measured or
       // estimated — these rows never soft-wrap) occupy EXACTLY the height the
       // full tree would. (The store cap trims both to the same 1000 rows.)
-      const offStore = createSessionStore()
+      process.env.HERMES_TUI_MAX_MESSAGES = '1000'
+      const offStore = (() => {
+        try {
+          return createSessionStore()
+        } finally {
+          delete process.env.HERMES_TUI_MAX_MESSAGES
+        }
+      })()
       offStore.apply({ type: 'gateway.ready' })
       for (let i = 0; i < 1500; i++) {
         offStore.pushSystem(i % 5 === 4 ? `row-${i} marker\nsecond line\nthird line` : `row-${i} marker`)