Updates plugin-author and operator docs to reflect the four fixup
PRs (C1, C2, I1, I4) for self-review findings.
Stacked on C1+C2 so the docs reference behavior that lands in the
same wave; rebases to staging once those merge.
What changes:
* docs/memory-plugins/README.md
- New "Memory idempotency" section explaining MemoryWrite.id
contract: omit → plugin generates UUID; supplied → upsert
- "Replacing the built-in plugin" rewritten as a 6-step
operator runbook with concrete commands for -dry-run / -apply
/ -verify / MEMORY_V2_CUTOVER, including the failure path
("if -verify reports mismatches, do not flip the cutover flag")
- Added link to new CHANGELOG.md
* docs/memory-plugins/testing-your-plugin.md
- New TestMyPlugin_IDIsIdempotencyKey example: write same id
twice, assert single row + updated content
- "What the harness does NOT cover" expanded with two new
operational gates: backfill twice → no double; verify-mode
reports zero mismatches
* docs/memory-plugins/pinecone-example/README.md
- Wire-mapping table updated: id (caller-supplied) → Pinecone
vector id (upsert); id (omitted) → plugin-generated UUID
- Production-hardening checklist gained an idempotency-key item
* docs/memory-plugins/CHANGELOG.md (new)
- Captures the four fixup PRs in one place with severity-ordered
summary, plugin-author action items, and remaining open
follow-ups (#289, #291, #293) for transparency
No code changes. Docs-only PR.
