Asset ownership — code owners for assets (v0.3.24)

[SylonZero]

What

Assets can now have one or more declared owners — like code owners. Ownership is routing and visibility, not an ACL: no approval gates or edit permissions. Unlike plan assignees (derived from task assignment), ownership is explicit — a durable responsibility with no activity to derive it from.

• asset_owners join table, both dialects. The postgres migration is hand-written per house convention (postgres has no drizzle snapshots past 0000); sqlite generated.
• setAssetOwners mutation + setAssetOwnersAction (with product-access check), ownersByAsset query helper feeding getProduct and getAssetDebtInfo, new getOwnedAssets rollup.
• Owner picker in the asset edit sheet; OwnerAvatars stacks on asset cards and Tech Debt Register groups.
• "Assets I Own" on My Work: health, effective debt score (manual override or severity-weighted derived), open-item count.
• MCP: ownerEmails on create_asset/update_asset (replaces the full owner set; [] clears), resolved via the shared-workspace email check.

Verification (drove the running app, sqlite)

• Applied migration via db:migrate; set owners through the real server-action surface → owner rows land, product page renders avatar stack (title="Owned by Alex Chen, Sarah Kim", fallbacks AC/SK), My Work shows "Assets I Own (1)" with debt score + health, work-items payload carries owners for the debt register.
• Probes: duplicate userIds in one call → deduped (unique index holds); cross-org user setting owners on an inaccessible asset → rejected ("Asset not found or not accessible") — this check was added after the probe initially got through; clearing with [] → rows removed, My Work section disappears.
• 167/167 vitest, tsc clean apart from pre-existing errors.

Notes

• Stacked on Work Items filters, Tech Debt Register scoring, Plans view persistence (v0.3.23) #26 — base is that branch; GitHub will retarget to master when Work Items filters, Tech Debt Register scoring, Plans view persistence (v0.3.23) #26 merges (delete-on-merge).
• Note: updateAssetAction/deleteAssetAction have the same missing-access-check pattern this PR fixed for owners — worth a small hardening pass (happy to file it as a CodePlans work item).

🤖 Generated with Claude Code