Add Schema Validation Coverage

Why

Connector schema coverage was uneven before this change. Five connectors (amazon, chase, chatgpt, reddit, usaa) shipped a schemas.ts with validateRecord; six others (github, gmail, ynab, codex, claude_code, slack) had no shape-check at all despite emitting hundreds of thousands of records into the local owner database. The connector authoring guide §3 calls schema-validation the floor — "a connector must never emit a record that looks right but is wrong" — but in practice that floor only existed for some.

The schemaless connectors are also the highest-volume ones. Before this change, the local DB contained 50k gmail records, 75k codex records, 253k claude_code records, and 349k slack records flowing through the pipeline with no shape enforcement. Any drift in upstream APIs, parser bugs, or accidentally-captured cruft would land silently in the DB, indistinguishable from valid data.

In addition, the validateRecord function was duplicated verbatim across all five existing schemas — same 17 lines of safeParse-and-format-issues logic — making new schemas more tedious to author and correct than they should be.

What Changes

• Add src/schema-registry.ts exporting makeValidateRecord(schemas) so every connector's schemas.ts becomes a registry plus one closure-binding line. Migrate the five existing schemas (amazon, chase, chatgpt, reddit, usaa) to use the helper.
• Author schemas.ts for the six previously-uncovered connectors: github, gmail, ynab, codex, claude_code, slack. Wire each into its connector's emit path. Schemas authored permissively-first per §3 of the authoring guide; tightening happens on observed failure.
• Add bin/replay-schemas.ts and bin/sample-records.ts — diagnostic tools that run every committed record through validateRecord and report pass/fail per stream. Used to ground the new schemas in real data and catch regressions on future schema edits.
• Reconcile codex's manifest to declare the previously-undeclared function_calls stream (47k records emitted; 0 declared).
• Bump connector versions: gmail 0.1.0→0.2.0; github, ynab, claude_code +0.1.0 minor; codex +0.1.0 (manifest also gains function_calls); slack +0.1.0.

Capabilities

Modified Capabilities

• reference-implementation-architecture: formalize the shared makeValidateRecord helper as the canonical pattern for connector schema validation; record the per-stream registry shape it expects.
• reference-implementation-governance: every connector with a parsers.ts and at least one stream SHALL ship a schemas.ts with shape-check coverage for every emitted stream.

Impact

• packages/polyfill-connectors/src/schema-registry.ts (new)
• packages/polyfill-connectors/connectors/{github,gmail,ynab,codex,claude_code,slack}/schemas.ts (new, 6 files)
• packages/polyfill-connectors/connectors/{amazon,chase,chatgpt,reddit,usaa}/schemas.ts (migrated to helper)
• packages/polyfill-connectors/connectors/*/index.ts (validateRecord wired in for the 6 new connectors; cast cleanup for amazon)
• packages/polyfill-connectors/manifests/{github,gmail,ynab,codex,claude_code,slack}.json (version bump; codex also adds function_calls)
• packages/polyfill-connectors/bin/{replay-schemas,sample-records}.ts (new diagnostic tools)
• No changes to public RS protocol, runtime contract, or downstream consumers.

Validation evidence

771,485 real owner records validated across 11 connectors. 9 of 11 pass at 100%; usaa passes at 99.4% (6 records flag legitimate data-quality issues already documented as a usaa-followup); reddit at 0% (DB still holds v0.1 records, schema is v0.2 — known, requires re-ingest).