Resolves #13974 Related: #13835

SemanticGraphExtractor.executeTriVectorExtraction() now returns typed failure descriptors instead of bare null for REM failure paths, while successful extraction still returns the existing Tri-Vector payload. DreamService.processUndigestedSessions() consumes those descriptors for deferReason / terminalForCadence, removes the payload-size defer heuristic, and keeps ingestion failures retryable.

Evidence: L2 (focused unit coverage for extractor failure descriptors plus DreamService digest-state consumption) -> L2 required (internal REM state-machine contract). No residuals.

Deltas from Ticket

• Kept ConsumerFriction V1 stable: no new symptom enum, cadence-specific deferReason remains separate.
• Preserved a legacy bare-null fallback in DreamService as retryable schema-failure, so old-style stubs or unexpected nulls do not silently defer sessions.
• Removed the ADR 0019-defensive localModels?.chat?.safeProcessingLimitTokens heuristic at the DreamService decision point.

Test Evidence

• npm run agent-preflight -- ai/services/graph/SemanticGraphExtractor.mjs ai/daemons/orchestrator/services/DreamService.mjs test/playwright/unit/ai/services/graph/SemanticGraphExtractor.spec.mjs test/playwright/unit/ai/daemons/orchestrator/services/DreamService.spec.mjs
• npm run test-unit -- test/playwright/unit/ai/services/graph/SemanticGraphExtractor.spec.mjs
• npm run test-unit -- test/playwright/unit/ai/daemons/orchestrator/services/DreamService.spec.mjs
• npm run test-unit -- test/playwright/unit/ai/services/graph/SemanticGraphExtractor.spec.mjs test/playwright/unit/ai/daemons/orchestrator/services/DreamService.spec.mjs

Post-Merge Validation

• Optional operator observation: next REM cycle surfaces typed deferReason values in per-session telemetry when provider failures occur.

Commits

• 60f0f59431 - fix(ai): expose REM extractor failure terminality (#13974)

Authored by Euclid (GPT-5, Codex Desktop). Session 019ef378-527d-7393-bc74-ec3a1d3f2ddf.