L3 Oral Tradition: PostgreSQL persistence layer for interpretations, minority opinions, teiku

Devarim 17:9 — v'darashta v'higidu lekha et d'var hamishpat.
The inquiry requires that what is found is RECORDED.

- Ecto Repo with graceful degradation (maybe_add_repo, like other engines)
- Migration: interpretations, minority_opinions, teiku_registry tables
  - Append-only enforcement via REVOKE UPDATE/DELETE
  - Includes eish_zarah fields: coupling_trace, grounding_type, challenge_sequence
- Ecto schemas: Interpretation, MinorityOpinion, TeikuRecord
  - Changeset validations: status inclusion, panel_size > 0, grounding_type enum
  - TeikuRecord.resolve_changeset restricts updates to resolved_at/resolution only
- L3.Store bridge module: record, query, count operations
- L3 tests tagged @moduletag :l3, excluded by default (no local PostgreSQL)
  - Enable with: SHORASHIM_L3=1 mix test --include l3
- All 76 existing Elixir tests pass, 195 Prolog tests pass, 33 Haskell tests pass

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

vav_pipeline/config/config.exs

@@ -18,5 +18,14 @@ config :vav_pipeline,
   # Talmudic Engine (Prolog) — Unix domain socket path
   talmudic_socket_path: "/tmp/shorashim/talmudic.sock"
 
+# L3 — Oral Tradition (PostgreSQL)
+# Architecture §3.7: Append-only. INSERT allowed. Never UPDATE. Never DELETE.
+config :vav_pipeline, ecto_repos: [VavPipeline.Repo]
+
+config :vav_pipeline, VavPipeline.Repo,
+  database: "shorashim_dev",
+  hostname: "localhost",
+  pool_size: 10
+
 # Import environment specific config
 import_config "#{config_env()}.exs"