Update Claude ACP runtime to 0.88.0

[jsgrrchg]

Upgrade the bundled Claude ACP runtime from 0.85.1 to 0.88.0, bringing upstream fixes for cancellation, session closure and prompts stuck during background-task followups. The updated runtime exposes Haiku 5.5 through the haiku alias alongside Sonnet 5.5.

Regenerate the isolated lockfile and published baseline, including all 72 JavaScript modules. Claude Agent SDK and all eight native packages are pinned to 0.3.293, with ACP SDK 1.7.0. Update the watcher expectations and runtime compatibility documentation.

Validation

• Runtime preparation and dependency integrity/native-version checks passed.
• 56 tests passed: 9 preparation/watcher/mock tests, 6 runtime contracts and 41 model-selection/chat-status tests.
• Linux x64 smoke passed with Claude Code 2.1.293: Sonnet 5.5 selection, exact provider request ID, real Read tool execution and cancellation against a local mock.
• A separate temporary local mock probe verified the Haiku 5.5 catalog entry, claude-haiku-5-5 provider request ID, Read tool followup and cancellation.
• ESLint for the changed watcher test and git diff --check passed.

Native Windows/macOS and packaged application validation remain for CI. The separate Claude Code terminal settings still use their existing static model list.

Closes #512.
Closes #513.