refactor(pty): rename model-facing tools to terminal_* and harden teardown

Rename the six model-facing tools pty_* -> terminal_* and align every
description, guidance section, ACP card title, and rendered result to
terminal terminology. Package and service internals keep their technical
PTY names (PtyService, "unknown PTY session", node-pty).

Harden the local backend teardown:
- a failed close is retryable: drop the memoized rejection so a later
  terminal_close re-runs against the live process table
- service disposal clears the backend, reservation, and owner-cleanup
  registries even when a close fails
- stop readiness polling before teardown so an in-flight send settles as
  session_exit instead of a mis-inferred wait reason
- bound the sanitizer's pending buffer against unterminated escape runs

Update the tool catalog, package READMEs, the bilingual Agent Note, and the
acp/headless pty-tools snapshots to match.

packages/pty/pty-local/tests/sanitize.spec.ts

@@ -3,7 +3,7 @@ import { normalizeTerminalText, TerminalSanitizer } from '@deepseek-ai/dsh-pty-l
 
 describe('TerminalSanitizer', () => {
   it('removes split CSI and owned OSC prompt markers', () => {
-    const sanitizer = new TerminalSanitizer()
+    const sanitizer = new TerminalSanitizer(64)
     expect(sanitizer.push('red\x1b[3')).toEqual({ text: 'red', prompt: false })
     expect(sanitizer.push('1m text\x1b[0m\r\n')).toEqual({ text: ' text\n', prompt: false })
     expect(sanitizer.push('\x1b]133;')).toEqual({ text: '', prompt: false })
@@ -11,7 +11,7 @@ describe('TerminalSanitizer', () => {
   })
 
   it('drops unrelated OSC, short escapes, BEL, and incomplete trailing escape', () => {
-    const sanitizer = new TerminalSanitizer()
+    const sanitizer = new TerminalSanitizer(64)
     expect(sanitizer.push('a\x1b]0;title\x1b\\b\x1b7c\x07')).toEqual({ text: 'abc', prompt: false })
     expect(sanitizer.push('tail\x1b')).toEqual({ text: 'tail', prompt: false })
     expect(sanitizer.flush()).toBe('')
@@ -24,4 +24,39 @@ describe('TerminalSanitizer', () => {
   it('normalizes CRLF and standalone carriage returns', () => {
     expect(normalizeTerminalText('a\r\nb\rc\x07')).toBe('a\nb\nc')
   })
+
+  it('bounds and discards unterminated control sequences through their terminators', () => {
+    const oscBel = new TerminalSanitizer(8)
+    expect(oscBel.push(`\x1b]0;${'x'.repeat(16)}`)).toEqual({ text: '', prompt: false })
+    expect(oscBel.push('more\x07tail')).toEqual({ text: 'tail', prompt: false })
+
+    const oscSt = new TerminalSanitizer(8)
+    oscSt.push(`\x1b]0;${'x'.repeat(16)}`)
+    expect(oscSt.push('more\x1b')).toEqual({ text: '', prompt: false })
+    expect(oscSt.push('\\tail')).toEqual({ text: 'tail', prompt: false })
+
+    const oscDirectSt = new TerminalSanitizer(8)
+    oscDirectSt.push(`\x1b]0;${'x'.repeat(16)}`)
+    expect(oscDirectSt.push('more\x1b\\tail')).toEqual({ text: 'tail', prompt: false })
+
+    const oscFalseSt = new TerminalSanitizer(8)
+    oscFalseSt.push(`\x1b]0;${'x'.repeat(16)}`)
+    oscFalseSt.push('\x1b')
+    expect(oscFalseSt.push('more')).toEqual({ text: '', prompt: false })
+    expect(oscFalseSt.push('\x07tail')).toEqual({ text: 'tail', prompt: false })
+
+    const oscNonTerminatingEscape = new TerminalSanitizer(8)
+    oscNonTerminatingEscape.push(`\x1b]0;${'x'.repeat(16)}`)
+    expect(oscNonTerminatingEscape.push('more\x1bxmore\x07tail')).toEqual({ text: 'tail', prompt: false })
+
+    const csi = new TerminalSanitizer(8)
+    expect(csi.push(`\x1b[${'1'.repeat(16)}`)).toEqual({ text: '', prompt: false })
+    expect(csi.push('123')).toEqual({ text: '', prompt: false })
+    expect(csi.push('mtext')).toEqual({ text: 'text', prompt: false })
+
+    const flushed = new TerminalSanitizer(8)
+    flushed.push(`\x1b]0;${'x'.repeat(16)}`)
+    expect(flushed.flush()).toBe('')
+    expect(flushed.push('text')).toEqual({ text: 'text', prompt: false })
+  })
 })