Modular candidate vs production

Package syntology/ is an additive modular kernel described in UPGRADE_CANDIDATE.md (present on fresher local trees; may not yet be on origin/main). It does not replace production until promotion gates pass.

Why

Collapses duplicated concerns: env loading, Neo4j tiers, drivers, corpus paths, ingest chain table, template registry, Bedrock/S2 clients, job registration, QC suite table.

Commands (when package present)

./venv/bin/python3 -m syntology doctor
./venv/bin/python3 -m syntology qc
./venv/bin/python3 -m syntology parity          # + --live
./venv/bin/python3 -m syntology census
./venv/bin/python3 -m syntology chain

Design rules

Additive — legacy path keeps working.
Single source — re-export existing ONE-way modules (provenance, bedrock_client, write_ledger, …); parity asserts object identity.
Registries over scatter.
Parity before promotion.
Fail loud — no silent writer→reader fallback.

Production vs candidate

Concern	Production today	Candidate
ASGI entry	`main:app`	`syntology.serving.app:create_app(legacy=True)` then carve routes
Index on request	`ensure_indexes` risk (F-06)	assert-only
Corpus paths	many literals	`corpus.locate()`
Ingest definition	inline in `06`	`stages.INGEST_CHAIN` (+ tripwire vs 06)

Promotion is one caller at a time; see UPGRADE_CANDIDATE §5 worklist.