feat(pipeline): skill phase kind + PhaseRunner seam + halt/answer/resume

[saucam]

What

Third slice: phase execution + the halt → answer → resume path. Still dark — pipeline off by default.

• makeSkillPhaseKind(runner?) — the "skill" phase kind. fn skills run natively (no backend); prompt / slash skills drive through an injectable PhaseRunner (the backend seam). With no runner configured, a prompt/slash skill fails with a clear reason, so the kind stays usable in pure tests and degrades safely.
• PhaseRunner (runner.ts) — the seam between a phase and a backend (runPrompt with per-phase provider / model for cross-provider-per-phase routing). The SessionManager-backed adapter that actually drives a worker turn lands in a follow-up.
• PipelineManager.answer(id, requestId, { approved, value }) — the daemon side of halt → answer-from-a-frontend → resume (§4.1, §5.3): resolves a halted phase (pass/fail) and continues advancing to the next halt or terminal. Persists across restart.

Verification

• bun test src/daemon/pipeline — 42 pass / 0 fail (16 new: skill-kind + answer/resume)
• tsc --noEmit — clean project-wide
• biome check — clean

Stacked

Base = feat/sdlc-pipeline-wiring (#205). This branch also carries a one-line lint fix (import type in manager.ts) that the rebased stack applies to #204/#205 as well.

Deferred to follow-ups

• PR feat(web): surface remaining context-window utilization #4 — a SessionManager-backed PhaseRunner: a worker session per phase actually driving a backend turn (needs the fake-provider integration harness).
• PR perf: cache MemoryEngine vector matrix instead of reloading per recall #5 — additive protocol (pipeline.* messages, SessionInfo.phase) + the §10 frontend halt-surfacing UX (answer a blocker from Web/Telegram).

🤖 Generated with Claude Code

[github-actions]

🟡 Medium — Uncaught exceptions in native fn skills

If a native fn skill throws an exception during execution, the error will propagate directly and reject the execution promise. Wrapping the skill execution in a try-catch block allows capturing the error and returning a graceful failure outcome (outcome: "failed") so the pipeline status can be updated gracefully in the database.

Suggested change

	}
	if (skill.kind === "fn") {
	try {
	const res = await skill.run(ctx);
	return { outcome: "passed", summary: res.summary, artifacts: res.artifacts };
	} catch (err: any) {
	return { outcome: "failed", reason: `Skill execution failed: ${err?.message ?? err}` };
	}
	}

[github-actions]

🤖 Gemini code review

This PR introduces the skill phase execution flow (with PhaseRunner abstraction for external model/slash skills) and the halt-answer-resume mechanism for pipeline execution.

Findings: 🔴 0 · 🟠 0 · 🟡 1 · 🟢 0

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_{Tokens spent · ⬆️ Input: 4,569 · ⬇️ Output: 238 · Σ Total: 9,452
Total may be higher due to thinking token counts.}

[saucam]

Addressed the Gemini finding: skill-kind.ts now wraps native fn skill execution in try/catch, returning a graceful outcome:"failed" attributed to the skill. (The engine-level guard from #204 already prevents a crash; this adds a clearer, skill-scoped failure reason.) Added a test for the throwing-fn path.