[enhancement] ConceptIngestor follow-ups post-#10035 — hoist concept-graph pass to cycle-scope + dedicated spec + observability polish

Context

Follow-up items surfaced during the self-review of PR #10084 (resolves #10035). The refactor landed cleanly (all 30 tests green), but four polish items were deferred as explicit out-of-scope flags rather than smuggled into the main PR. This ticket bundles them because all four touch the same two files (ai/daemons/DreamService.mjs + ai/daemons/services/ConceptIngestor.mjs) and sequencing them together avoids conflicting patches.

The Four Items

1. Hoist inferConceptGraphGaps call from per-session to cycle-scope (efficiency)

Problem: GapInferenceEngine.executeCapabilityGapInference(session, payload) invokes both inferTestGapsFromSession (session-scoped, correct) AND inferConceptGraphGaps (ontology-scoped, wasteful in a loop) once per session. DreamService's REM loop iterates N sessions per cycle, so the concept-graph pass runs N times with the same output. Correctness is unaffected (writes are idempotent), but it's wasted work that grows with ontology + session count.

Fix: Extract inferConceptGraphGaps to a standalone method callable on GapInferenceEngine; invoke it once from DreamService.processUndigestedSessions after the per-session loop, before runGarbageCollection.

2. Create test/playwright/unit/ai/daemons/services/ConceptIngestor.spec.mjs (coverage)

Problem: Currently tested only indirectly via DreamService integration tests. The service's contract at the unit level isn't locked in.

Coverage targets:

• Hash-based differential sync — skip path (unchanged payload) + upsert path (changed payload)
• Orphan detection (no IMPLEMENTED_BY → logger.warn)
• Edge-type normalization via CONCEPT_EDGE_TYPES constants
• Stub-node seeding by namespace (file: → FILE, ext: → EXT, fallback → CONCEPT)
• Idempotency (two consecutive sync calls produce identical graph state)
• Stats return shape ({conceptsProcessed, conceptsUpserted, conceptsSkipped, edgesReplaced, orphansDetected, errors})

3. Log syncConceptsToGraph returned stats in DreamService (observability)

Problem: await ConceptIngestor.syncConceptsToGraph() returns a stats object that DreamService currently discards. The return shape exists for observability; dropping it on the floor means cycle-time / differential-sync benefits aren't visible in REM cycle logs.

Fix: Capture the returned stats; emit via logger.info('[DreamService] Concept ingestion: ...', stats) before the per-session loop begins.

4. Consolidate per-orphan logger.warn into summary (log hygiene)

Problem: ConceptIngestor.syncConceptsToGraph emits one logger.warn per orphan concept. At 17 orphans today × N REM cycles per day = log spam. Grows linearly with ontology size.

Fix: Accumulate orphan IDs/names into an array during the sync loop; emit a single summary warn at completion with count + top N names (e.g., first 10 by weight).

Acceptance Criteria

• inferConceptGraphGaps hoisted from per-session to cycle-scope in DreamService
• test/playwright/unit/ai/daemons/services/ConceptIngestor.spec.mjs created with the six coverage targets above
• Stats logging surfaces in DreamService REM cycle output
• Orphan warnings consolidated into summary form
• Existing PR #10084 tests still pass (regression guard)

Origin Session ID

62d6f155-e57f-4279-9b59-36c9e4ecbc5e — surfaced in PR #10084 self-review comment

Related

• Parent epic: #10030 (Concept Ontology & Semantic Gap Inference)
• Origin PR: #10084 (merged) — Required Actions section of the self-review
• Sibling follow-ups filed alongside: #[config-lift threshold], #[ORPHAN_CONCEPT channel]