Epic: Organisational memory (conventions, expertise, conflicts) #16

Goal

Turn raw PR/issue/commit docs into team knowledge: unwritten conventions, who knows what, and which source wins when they disagree. Zero-LLM by default; an LLM is an optional upgrade. Every answer stays source-linked.

Issues

Order: #84, #85, #89 and #91 in parallel → #86, #87, #92 → #88. #84 and #91 both add an index schema version: whichever merges second bumps the number again.

Conventions for every issue

• Derived data lives in the index (rebuildable by waymark reindex) or in wiki docs under derived/; connector documents are never edited by derivation (the next sync would overwrite them).
• No new runtime dependency; no LLM required for any acceptance criterion.
• New user-facing behaviour is documented in docs/memory.md (created by the first issue that needs it) and in the README command table.

Definition of done

• waymark experts src/index on this repo names the people who changed it, with evidence ids.
• On a fixture with repeated review comments, a convention is derived, accepted, and shown in the agent start-up context.
• A superseded ADR ranks below its replacement and is marked in search results.
• Everything works with no llm configured.

Evidence

• Unblocked derives conventions from PR review feedback and maps expertise: https://getunblocked.com/
• PR review comments with file/line context are already ingested by the GitHub PR connector (MVP): renderPull in src/connectors/github/index.ts.