refactor(agent-launch): collapse the readiness budget to one flat timeout

The per-signal budget (marker 20s / quiet-window 8s) tied the timeout to how
readiness is DETECTED. The budget is really a property of how slowly an agent
can boot — a marker, a quiet window, and a process check all wait out the same
cold start — so one number covers all three signals.

Replaces draftPasteReadyBudgetMs() with DRAFT_PASTE_READY_TIMEOUT_MS: drops a
constant, a branch, and two tests, and removes the only reason a delivery path
needed to know which signal class it was using.

Cost: a launch that never emits DECSET 2004 now surfaces its 'prompt not sent'
toast at 20s instead of 8s. That is the failed-launch path only; successful
markerless delivery still resolves on the 1.5s quiet window as before.

src/main/runtime/orca-runtime.ts

@@ -418,7 +418,7 @@ import {
 } from '../../shared/tui-agent-config'
 import {
   createDraftPasteReadyScanner,
-  draftPasteReadyBudgetMs
+  DRAFT_PASTE_READY_TIMEOUT_MS
 } from '../../shared/draft-paste-ready-scanner'
 import { detectInstalledAgentsWithShellPathHydration, detectRemoteAgents } from '../ipc/preflight'
 import {
@@ -21374,7 +21374,7 @@ export class OrcaRuntimeService {
       // delivery paths do, instead of silently dropping the prompt (STA-3367).
       hardTimer = setTimeout(() => {
         void this.resolveDraftPastePtyIfAgentOwns(ptyId, agent).then(finish)
-      }, draftPasteReadyBudgetMs(readySignal))
+      }, DRAFT_PASTE_READY_TIMEOUT_MS)
     })
   }
 

src/main/runtime/startup-draft-paste-readiness.test.ts

@@ -6,18 +6,16 @@
  * scanner, the shared budget, and the fallback are all exercised.
  */
 import { beforeEach, afterEach, describe, expect, it, vi, type Mock } from 'vitest'
-import { draftPasteReadyBudgetMs } from '../../shared/draft-paste-ready-scanner'
+import { DRAFT_PASTE_READY_TIMEOUT_MS } from '../../shared/draft-paste-ready-scanner'
 import { OrcaRuntimeService } from './orca-runtime'
 
 const DECSET_BRACKETED_PASTE = '\x1b[?2004h'
 const CODEX_COMPOSER_PROMPT_RENDER = '\x1b[1m›\x1b[0m Ask Codex to do anything'
 const PTY_ID = 'pty-1'
 const HANDLE = 'term-1'
-// Why: pull the budgets from the shared policy rather than restating them, so
-// this fails if the runtime waiter ever stops consuming it. The literal values
-// are pinned once, in draft-paste-ready-scanner.test.ts.
-const CODEX_MARKER_BUDGET_MS = draftPasteReadyBudgetMs('codex-composer-prompt')
-const QUIET_WINDOW_BUDGET_MS = draftPasteReadyBudgetMs('render-quiet-after-bracketed-paste')
+// Why: the old budget that dropped the prompt, kept only to prove the waiter now
+// outlasts it. The current value is pinned in draft-paste-ready-scanner.test.ts.
+const OLD_DROPPED_AT_MS = 8000
 
 type RuntimeHost = {
   getLivePtyForHandle: (handle: string) => { pty: { ptyId: string } } | null
@@ -80,18 +78,18 @@ describe('waitForStartupDraftReady', () => {
     expect(vi.getTimerCount()).toBe(0)
   })
 
-  it('waits the full marker budget before giving up on a cold codex composer', async () => {
+  it('waits the full budget before giving up on a cold codex composer', async () => {
     const promise = waitForStartupDraftReady.call(host, HANDLE, 'codex')
     await Promise.resolve()
     observer?.(DECSET_BRACKETED_PASTE)
 
-    // The old markerless-length budget would already have resolved (to null) here.
-    await vi.advanceTimersByTimeAsync(QUIET_WINDOW_BUDGET_MS)
+    // The old budget would already have resolved (to null) here.
+    await vi.advanceTimersByTimeAsync(OLD_DROPPED_AT_MS)
     expect(getForegroundProcess).not.toHaveBeenCalled()
 
-    // Still inside the marker budget: a late glyph is the real ready proof, and
-    // must win over the ownership fallback.
-    await vi.advanceTimersByTimeAsync(CODEX_MARKER_BUDGET_MS - QUIET_WINDOW_BUDGET_MS - 1)
+    // Still inside the budget: a late glyph is the real ready proof, and must
+    // win over the ownership fallback.
+    await vi.advanceTimersByTimeAsync(DRAFT_PASTE_READY_TIMEOUT_MS - OLD_DROPPED_AT_MS - 1)
     observer?.(CODEX_COMPOSER_PROMPT_RENDER)
     await expect(promise).resolves.toBe(PTY_ID)
     expect(getForegroundProcess).not.toHaveBeenCalled()
@@ -105,7 +103,7 @@ describe('waitForStartupDraftReady', () => {
     const promise = waitForStartupDraftReady.call(host, HANDLE, 'codex')
     await Promise.resolve()
 
-    await vi.advanceTimersByTimeAsync(CODEX_MARKER_BUDGET_MS)
+    await vi.advanceTimersByTimeAsync(DRAFT_PASTE_READY_TIMEOUT_MS)
 
     await expect(promise).resolves.toBe(PTY_ID)
     expect(getForegroundProcess).toHaveBeenCalledWith(PTY_ID)
@@ -117,7 +115,7 @@ describe('waitForStartupDraftReady', () => {
     const promise = waitForStartupDraftReady.call(host, HANDLE, 'codex')
     await Promise.resolve()
 
-    await vi.advanceTimersByTimeAsync(CODEX_MARKER_BUDGET_MS)
+    await vi.advanceTimersByTimeAsync(DRAFT_PASTE_READY_TIMEOUT_MS)
 
     await expect(promise).resolves.toBeNull()
   })
@@ -127,7 +125,7 @@ describe('waitForStartupDraftReady', () => {
     const promise = waitForStartupDraftReady.call(host, HANDLE, 'codex')
     await Promise.resolve()
 
-    await vi.advanceTimersByTimeAsync(CODEX_MARKER_BUDGET_MS)
+    await vi.advanceTimersByTimeAsync(DRAFT_PASTE_READY_TIMEOUT_MS)
 
     await expect(promise).resolves.toBeNull()
   })

src/renderer/src/components/terminal-pane/pty-connection.ts

@@ -306,7 +306,7 @@ import { isWslUncPath } from '../../../../shared/wsl-paths'
 import { isTuiAgent, TUI_AGENT_CONFIG } from '../../../../shared/tui-agent-config'
 import {
   createDraftPasteReadyScanner,
-  draftPasteReadyBudgetMs
+  DRAFT_PASTE_READY_TIMEOUT_MS
 } from '../../../../shared/draft-paste-ready-scanner'
 import { sendAgentDraftPasteContent } from '@/lib/agent-draft-paste-content'
 import { writeTerminalPastePtyInput } from './terminal-pty-paste-writer'
@@ -4883,7 +4883,7 @@ export function connectPanePty(
       startupDraftHardTimer = setTimeout(() => {
         startupDraftHardTimer = null
         void deliverStartupDraftIfAgentOwnsPty()
-      }, draftPasteReadyBudgetMs(startupDraftReadySignal))
+      }, DRAFT_PASTE_READY_TIMEOUT_MS)
     }
     const armStartupDraftQuietTimer = (): void => {
       if (!startupDraftReadyScanner || startupDraftPasteSettled) {

src/renderer/src/lib/agent-paste-draft.ts

@@ -1,6 +1,6 @@
 import type { TuiAgent, GlobalSettings } from '../../../shared/types'
 import { TUI_AGENT_CONFIG } from '../../../shared/tui-agent-config'
-import { draftPasteReadyBudgetMs } from '../../../shared/draft-paste-ready-scanner'
+import { DRAFT_PASTE_READY_TIMEOUT_MS } from '../../../shared/draft-paste-ready-scanner'
 import { useAppStore } from '@/store'
 import {
   inspectRuntimeTerminalProcess,
@@ -68,8 +68,7 @@ export function getSettingsForAgentTabRuntimeOwner(
  * Returns true when the paste was issued, false on timeout or missing
  * PTY. `onTimeout` lets the caller surface a UI hint (e.g. toast) when
  * the agent doesn't reach a ready state. `timeoutMs` overrides the
- * per-signal readiness budget only; waiting for the PTY to spawn keeps its
- * own fixed budget.
+ * readiness budget only; waiting for the PTY to spawn keeps its own budget.
  *
  * Readiness combines DECSET 2004 with one agent-specific follow-up signal:
  *   1. `\x1b[?2004h` (DECSET 2004 — bracketed-paste-enable) on the PTY
@@ -110,7 +109,7 @@ export async function pasteDraftWhenAgentReady(args: {
   const settings = getSettingsForAgentTabRuntimeOwner(tabId)
   // Why: the readiness budget starts once the PTY exists, so a slow spawn
   // shortens nothing — a cold composer still gets its full window.
-  const budget = timeoutMs ?? draftPasteReadyBudgetMs(readySignal)
+  const budget = timeoutMs ?? DRAFT_PASTE_READY_TIMEOUT_MS
   const ready = await waitForAgentDraftInputReady(ptyId, budget, readySignal, settings)
   if (!ready) {
     // Why: fast-starting TUIs can emit the paste-ready escape sequence before
@@ -153,7 +152,7 @@ export async function pasteDraftToAgentPtyWhenReady(args: {
 
   const settings = getSettingsForAgentTabRuntimeOwner(tabId)
   const readySignal = agentConfig?.draftPasteReadySignal ?? 'render-quiet-after-bracketed-paste'
-  const budget = timeoutMs ?? draftPasteReadyBudgetMs(readySignal)
+  const budget = timeoutMs ?? DRAFT_PASTE_READY_TIMEOUT_MS
   const ready = await waitForAgentDraftInputReady(ptyId, budget, readySignal, settings)
   if (!ready) {
     const fallbackReady = agentConfig

src/shared/draft-paste-ready-scanner.test.ts

@@ -1,5 +1,8 @@
 import { describe, expect, it } from 'vitest'
-import { createDraftPasteReadyScanner, draftPasteReadyBudgetMs } from './draft-paste-ready-scanner'
+import {
+  createDraftPasteReadyScanner,
+  DRAFT_PASTE_READY_TIMEOUT_MS
+} from './draft-paste-ready-scanner'
 
 const DECSET_BRACKETED_PASTE = '\x1b[?2004h'
 const SHOW_CURSOR = '\x1b[?25h'
@@ -137,28 +140,10 @@ describe('createDraftPasteReadyScanner', () => {
   })
 })
 
-describe('draftPasteReadyBudgetMs', () => {
-  it('gives marker-gated signals room for a cold boot (STA-3367)', () => {
-    // Why: the marker is a positive proof, so waiting longer can only tolerate a
-    // slow first-run codex — it can never paste into a composer that isn't there.
-    expect(draftPasteReadyBudgetMs('codex-composer-prompt')).toBe(20000)
-    expect(draftPasteReadyBudgetMs('render-cursor-after-bracketed-paste')).toBe(20000)
-  })
-
-  it('keeps the markerless quiet window tight', () => {
-    // Why: silence is a guess, not a proof; a longer budget just delays a wrong answer.
-    expect(draftPasteReadyBudgetMs('render-quiet-after-bracketed-paste')).toBe(8000)
-  })
-
-  it('gives every marker-gated signal a strictly larger budget than the quiet window', () => {
-    // Guards the invariant rather than the numbers: a new marker signal added to
-    // the scanner must not silently inherit the tighter markerless budget.
-    const quiet = draftPasteReadyBudgetMs('render-quiet-after-bracketed-paste')
-    for (const signal of [
-      'codex-composer-prompt',
-      'render-cursor-after-bracketed-paste'
-    ] as const) {
-      expect(draftPasteReadyBudgetMs(signal)).toBeGreaterThan(quiet)
-    }
+describe('DRAFT_PASTE_READY_TIMEOUT_MS', () => {
+  it('leaves room for a cold-boot composer (STA-3367)', () => {
+    // Why: the reported drop was a first-run codex composer mounting past the old
+    // 8s budget. Pinned once here; every delivery path imports rather than restates it.
+    expect(DRAFT_PASTE_READY_TIMEOUT_MS).toBe(20000)
   })
 })

src/shared/draft-paste-ready-scanner.ts

@@ -20,32 +20,21 @@ export type DraftPasteReadyScanResult = {
   armQuietTimer: boolean
 }
 
-// Why: the markerless quiet-window signal guesses readiness from output silence,
-// so a long budget just delays a wrong answer. Keep it tight.
-const QUIET_WINDOW_READY_TIMEOUT_MS = 8000
-// Why: marker-gated signals (Codex '›', opencode show-cursor) are positive
-// readiness proofs — the paste fires only when the marker actually renders, so a
-// longer budget can never paste prematurely; it only tolerates a slow cold boot.
-// First-run codex on a cold app can take >8s to mount its composer, past which
-// the old budget gave up and dropped the launch prompt (STA-3367).
-const MARKER_READY_TIMEOUT_MS = 20000
-
 /**
- * How long a delivery path should wait for `readySignal` before falling back.
+ * Backstop for every draft-paste delivery path: how long to wait for a ready
+ * signal before falling back to a best-effort, ownership-checked paste.
  *
- * Lives beside the scanner because the budget is a property of the signal — only
- * this module knows which signals are marker-gated — not of the calling path. All
- * three draft-delivery owners (renderer tab paste, renderer startup paste, main
- * runtime startup paste) consume this so the policy cannot drift between them.
+ * One budget for all signals. The value is a property of how slowly an agent can
+ * boot, not of how readiness is detected — a marker, a quiet window, and a
+ * process check all wait on the same cold start. First-run codex on a cold app
+ * can take >8s to mount its composer, past which the old budget gave up and
+ * dropped the launch prompt (STA-3367).
  *
- * This is a backstop, not a correctness gate: every caller must still attempt a
- * best-effort delivery when the agent owns the PTY after the budget expires.
+ * Lives beside the scanner so all three delivery owners (renderer tab paste,
+ * renderer startup paste, main runtime startup paste) share one policy and
+ * cannot drift apart.
  */
-export function draftPasteReadyBudgetMs(readySignal: DraftPasteReadySignal): number {
-  return readySignal === 'render-quiet-after-bracketed-paste'
-    ? QUIET_WINDOW_READY_TIMEOUT_MS
-    : MARKER_READY_TIMEOUT_MS
-}
+export const DRAFT_PASTE_READY_TIMEOUT_MS = 20000
 
 /**
  * Pure, incremental scanner shared by the renderer and main-process draft-paste