vscode: Backlog title-count reflects the active view mode

[amrmelsayed]

PIR Review: vscode Backlog title-count reflects the active view mode

Fixes #911

Summary

The Backlog tree title used to read Backlog (47) (the unfiltered spawnable total) even when the view was in mine-only mode showing just 3 rows — the most prominent integer on the view disagreed with what was rendered below. This PR rewrites the title to Backlog (3 of 47) in mine-only mode and Backlog (47) in show-all mode (option 2 from the issue), and wires the title-update into the codev.backlogShowAll config-change listener so it refreshes in lockstep with the tree rather than waiting for the next overview tick.

Files Changed

• packages/vscode/src/views/backlog-filter.ts (+54 / -3) — new visibleBacklogCount and formatBacklogTitle helpers; spawnableBacklog moved in from backlog.ts so the vscode-free module owns all three primitives the title and the provider share.
• packages/vscode/src/views/backlog.ts (+5 / -10) — drops the local spawnableBacklog; imports + re-exports it from backlog-filter.ts so existing call sites keep working.
• packages/vscode/src/extension.ts (+22 / -4) — updateListViewTitles now calls visibleBacklogCount + formatBacklogTitle for the backlog row; readBacklogShowAll hoisted above the title helper; showAll-config-change listener also calls updateListViewTitles().
• packages/vscode/src/__tests__/backlog-filter.test.ts (+131 / -1) — coverage for spawnableBacklog, visibleBacklogCount, formatBacklogTitle. Existing filterMine coverage preserved.
• codev/plans/911-vscode-backlog-tree-title-coun.md (new, +94) — approved plan.
• codev/state/pir-911_thread.md (new, +25) — builder thread.

Commits

• b6e98cf4 [PIR vscode: Backlog tree title-count should reflect the active view mode, not the total spawnable set #911] Plan draft
• 8ee5e308 [PIR vscode: Backlog tree title-count should reflect the active view mode, not the total spawnable set #911] Thread: plan phase complete
• c614bf76 [PIR vscode: Backlog tree title-count should reflect the active view mode, not the total spawnable set #911] Backlog title-count reflects active view mode
• 9512bbd8 [PIR vscode: Backlog tree title-count should reflect the active view mode, not the total spawnable set #911] Thread: implement phase complete

(porch-managed phase-transition / gate commits omitted.)

Test Results

• pnpm check-types: ✓ pass
• pnpm lint: ✓ pass (eslint, zero warnings)
• pnpm test:unit: ✓ pass — 113 tests across 10 files, ~20 new for the title-count path
• pnpm package (esbuild bundle, production): ✓ pass
• Manual verification at the dev-approval gate: ✓ approved by the human

Architecture Updates

No arch changes needed. This PR works inside the existing Backlog-view module boundary (backlog.ts provider + backlog-filter.ts pure helpers) — the only structural shift is moving spawnableBacklog from backlog.ts (vscode-dependent) into backlog-filter.ts (vscode-free) so the title helper can reuse it from the vitest harness. That mirrors the precedent filterMine established in #809; not a new pattern.

Lessons Learned Updates

No new durable lessons. The "keep vscode-free helpers in backlog-filter.ts so vitest can test them without vscode mocks" pattern is already documented implicitly by filterMine's existence — this PR just continues that pattern. A re-statement in lessons-learned.md would be churn, not signal.

One contextual observation worth recording in the PR body (not the lessons file): two coupled bugs were closed at once — the count itself, and the refresh trigger. The count being wrong would have been obvious; the refresh trigger being wrong would have been masked by the periodic overview poll (the title would have updated within 60s of any showAll toggle, so it looked "almost right" most of the time). Worth knowing for future title/badge-counter work: any view title that depends on user-toggleable state needs to be refreshed on the toggle's listener, not just on the data-change listener.

Things to Look At During PR Review

• visibleBacklogCount's currentUser fallthrough (backlog-filter.ts). When mine-only is active but currentUser is null (gh unavailable), filterMine is a no-op, so visible == total. The title helper short-circuits this to plain Backlog (T) rather than Backlog (T of T) — matches the safety branch in BacklogProvider.orderedSpawnable and the third acceptance criterion in the issue.
• Hoisting readBacklogShowAll in extension.ts. The reader was previously declared inside the backlog-toggle listener block (around line 358 pre-change). The hoist moves it above updateListViewTitles so the title helper can call it on every refresh. The original site (now the listener) uses the hoisted reader.
• Title format choice. Option 2 (Backlog (V of T)) was the issue's mild preference. Options 1 and 3 are also acceptable and the helper could be swapped to either with a one-line change in formatBacklogTitle. Worth one re-read by the architect at PR review to confirm.
• src/test/backlog.test.ts left in place. The vscode-test (Electron) harness still has the old spawnableBacklog test file; it imports from backlog.ts which re-exports the moved helper, so it still passes. Deleting it would be cleanup but goes beyond the issue's "purely a count/title-string fix" scope.

How to Test Locally

For reviewers pulling the branch:

• View diff: VSCode sidebar → right-click builder pir-911 → Review Diff (auto-detects the default branch)
• Run dev server: VSCode sidebar → Run Dev Server, or afx dev pir-911
• What to verify (mapped from the plan's Test Plan):
  • Open the Backlog view in mine-only mode (default): title reads Backlog (V of T) where V matches the row count and T matches the unfiltered spawnable total. With nothing assigned to you, expect Backlog (0 of T) plus the empty-state placeholder from vscode: backlog view — toggle between 'mine only' (default) and 'all' #809.
  • Toggle the eye icon to show-all: title immediately becomes Backlog (T), row count matches.
  • Toggle back to mine-only: title immediately reverts to Backlog (V of T). No stale count waiting for the next overview tick.
  • Other tree titles (Builders, Pull Requests, Recently Closed) still render with their existing (N) format — no regression.