feat(comms): carry an optional issue or PR ref on asks (RIG-5173)

[rigel-mintaka]

This PR is part of a stack containing 5 PRs:

1. main
2. feat(store): status board tables, patch merge and board reads (RIG-5170) #2212
3. "feat(comms): carry an optional issue or PR ref on asks (RIG-5173)" (this PR)
4. feat(board): derive board refs, PR gates and stacks from stored rows (RIG-5171) #2231
5. feat(mirror): mirror asks and topics to forge issues and PRs (RIG-5181) #2275
6. feat(board): agent board RPCs, roster summary and board events (RIG-5172) #2285

What

First half of status-board T5: Ask.ref from end to end.

• Proto: Ask gains string ref = 4, the issue or PR the ask concerns, in the board ref grammar (RIG-12 or owner/repo#12). Go and both TS clients are regenerated.
• Edge: askFromWire canonicalizes the ref with refs.Parse (forge owner and repo lowercased). It refuses anything that is not exactly one ref with invalid_argument, and nothing is stored. askToWire returns the ref.
• Store: no change. The base PR (feat(store): status board tables, patch merge and board reads (RIG-5170) #2212) already persists Ask.Ref in the ask JSONB, and AnswerAsk copies the ask, ref included, into the answer snapshot.
• Spec: docs/specs/product/compass.md gains "An ask may name the issue or pull request it concerns", with two scenarios.
• Every wire-to-ask path goes through blocksFromWire → askFromWire: PostMessage, PostAsAccount and PostAsAccountByName. The test-only agent-update helper uses it too.

Not in this PR: the board's asks section

T5's other half fills AgentBoard.asks from AsksByAuthor. Its only caller is T4's ListBoardsAsAccount (RIG-5172), which doesn't exist yet. Without that caller the function fails the unused lint and would do nothing. compass-server (T4 owner) and I agreed the interface: func (c *Comms) boardAsks(ctx, viewer, agent store.AccountID) ([]*compassv1.BoardAsk, error) (24h window, max 20, newest first, viewer-clipped). It lands with or right after T4, together with its viewer-clip test. RIG-5173 stays open until then.

The comms_post_ask ref parameter is T8 (agent lane).

Tests

• Red first: the ask-field classification test failed on the new proto field. TestAskFromWireRef, TestAskRefRoundTrip and TestPostMessageRejectsMalformedAskRef were written before the mapping.
• TestAskRefRoundTrip follows the ask through post → ListMessages → RespondToAsk → ListMessages. The ask and the answer snapshot both carry the canonical ref.
• Mutations go red: dropping the outbound ref, skipping canonicalization, accepting a malformed ref, and the store read dropping ref.
• Full internal/comms pgtest suite: 217 PASS, 0 FAIL, 0 SKIP. golangci-lint (with and without the pgtest tag) reports 0 issues. nilaway is clean. rumdl is clean, and design-ledger-gate passes.

Stacked on #2212 (T2, compass-server). Its head is unchanged.

Spec-impact: docs/specs/product/compass.md (new ask-ref requirement)
Ledger-impact: none

Refs RIG-5173

Co-authored-by: Matt Wilkinson matt@rigel.build

[linear-code]

RIG-5173

[rigel-mintaka]

Review at head 08881500: high 0, medium 0, low 0, nit 0

• Scope: the whole diff, all lenses, 1 round. It covers T5 bullet 1 (Ask.ref from end to end) and the spec. The board-asks half is held back until T4, as the body explains.
• Round 1: 3 low. (1) The malformed-ref test passed without checking when its read failed; fixed. (2) A test that only checked a field copy; deleted. (3) The test-only agent-update helper dropped ref; it now goes through askFromWire. All folded.
• Checks: the internal/comms pgtest suite passes (217, 0 skipped). golangci-lint (with and without pgtest) reports 0 issues, nilaway is clean, rumdl is clean, design-ledger-gate passes. Red first; 4 mutations go red.

[github-actions]

Compass engineering docs preview: https://compass-comms-rig-5173-ask-r.compass-eng-docs.pages.dev

Deployed from compass-comms/rig-5173-ask-ref at 2484fb6.

Changed pages:

• docs/specs/product/compass.md

[rigel-mintaka]

Rebased onto #2212 at 51287001; head is now 7ab717a8. jj interdiff against the approved 08881500 shows 0 files changed. Re-requesting review on the new head.

[rigel-mintaka]

Rebase note: restacked on #2212 (51287001). Interdiff from approved head 08881500 to 7ab717a8 is empty.

[rigel-mintaka]

Rebase note: rebased onto main (b1e8515) after RIG-5326 and RIG-5324 landed. Interdiff from approved head 7ab717a8 to 2484fb68 is empty.