Introduce a run context for the enrichment pipeline's runJob

[cursor]

Spec: Fowler-style refactoring review (cloud agent, 2026-08-05). Refactor only — no behavior change.

What to change

In lib/enrichment/process.ts:

1. runJob takes 18 positional parameters (~426–445) and runs ~300 lines. Introduce a parameter object (e.g. EnrichmentRunContext holding repository, gateway, blob store, transcriber, place resolver, search, memory repository, projects/proposals/rejected names, thread repository, push, artifacts, embeddings) built once per processPendingEnrichments call.
2. Dependency wiring — the ~50 lines of options.x ?? getX(environment) at the top of processPendingEnrichments (~792–835) become an extracted resolveEnrichmentDeps(options).
3. The needs_attention result mapping is copy-pasted 4× in runJob (failed job ~446–453, thread missing ~470–477, capability refusal ~518–525, catch-all ~718–725). Extract attentionResults(targetCaptureIds, threadId, reason, retryable).
4. The nested ternary computing idempotencyKey in queueJobsForThreads (~295–301) becomes a named enrichmentJobKey(...) decision function.
5. Extract the memory-tool construction (~544–577) and the project matching/propose block (~620–645) into named functions.

Out of scope: the enrichment repositories (separate ticket); any change to job semantics, idempotency-key values, or retry policy.

Acceptance criteria

• runJob receives one context object plus the job; no function in the file takes more than ~5 parameters
• The four needs_attention blocks share one helper; idempotency keys are produced by one named function with unchanged values
• mise run lint passes; tests/enrichment-*.spec.ts pass unchanged