fix(claude-code-cli): ignore informational follow-up prompts

[mastertyko]

TL;DR

What: Stops Claude Code follow-up/result notifications from being treated as user prompts.
Why: Those informational follow-ups were polluting prompt context and could change downstream model behavior unexpectedly.
How: Filter async-job-result and follow-up-only user messages out of the prompt context builder, and lock the behavior with regression coverage.

What

This change teaches the Claude Code CLI stream adapter to ignore informational follow-up messages when it builds prompt history for the model.

Affected areas:

• src/resources/extensions/claude-code-cli/stream-adapter.ts
• src/resources/extensions/claude-code-cli/tests/stream-adapter.test.ts

Depends on #3414 for the shared async-jobs verifier blocker fix used by this branch.

Why

Closes #3168.

Claude follow-up notifications such as async job result messages are not real user prompts. When they were included in prompt history, they could steer the next model turn with noise that the user never actually said.

How

The stream adapter now treats async_job_result and other follow-up-only user messages as informational, excluding them from the prompt transcript that gets sent back to Claude. Regression tests cover both the ignored follow-up path and the normal user-prompt path.

Change type

• fix — Bug fix
• feat — New feature or capability
• refactor — Code restructuring (no behavior change)
• test — Adding or updating tests
• docs — Documentation only
• chore — Build, CI, or tooling changes

Scope

• pi-tui — Terminal UI
• pi-ai — AI/LLM layer
• pi-agent-core — Agent orchestration
• pi-coding-agent — Coding agent
• gsd extension — GSD workflow
• native — Native bindings
• ci/build — Workflows, scripts, config

Breaking changes

• No breaking changes
• Yes — described above

Test plan

• CI passes
• New/updated tests included
• Manual testing — steps described above
• No tests needed — explained above

Verified locally with the full CI mirror gate:

• npm run build
• npm run typecheck:extensions
• npm run test:unit
• npm run test:integration

The final truth phase was re-run in a plain verification clone on the exact branch head after a worktree-specific late verifier stall.

AI disclosure

• This PR includes AI-assisted code — prepared with Codex and verified as described in the test plan above.

[github-actions]

🟡 PR Risk Report — MEDIUM

Files changed	4
Systems affected	1
Overall risk	🟡 MEDIUM

Affected Systems

Risk	System
🟡 medium	Async Jobs

File Breakdown

Risk	File	Systems
🟡	src/resources/extensions/async-jobs/job-manager.ts	Async Jobs
⚪	src/resources/extensions/async-jobs/await-tool.test.ts	(unclassified)
⚪	src/resources/extensions/claude-code-cli/stream-adapter.ts	(unclassified)
⚪	src/resources/extensions/claude-code-cli/tests/stream-adapter.test.ts	(unclassified)