## PR-17 — Diagnostics UX: dependency graph and resolution trace

**Why:** Dependency failures must be explainable.

### Scope

* Add compiler diagnostics output:

  * resolved dependency graph
  * alias → project mapping
  * explanation of conflicts or failures

* Add CLI/API flag:

  * `--explain-deps`

### Deliverables

* human-readable resolution trace

### Tests

* snapshot tests for diagnostics output (best-effort)

### Acceptance

* Users can debug dependency and linking issues without guesswork.

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## Suggested Execution Order

1. PR-09 → PR-10 → PR-11
2. PR-12 → PR-13
3. PR-14 → PR-15
4. PR-16 → PR-17

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## Notes for Junie

* Keep all v0 decisions simple and deterministic.
* Prefer explicit errors over silent fallback.
* Treat `archive-pbs/test01` as the north-star integration scenario.
* No background work: every PR must include tests proving behavior.