fix(claude): statusline distinguishes an empty graph from a missing one (#185)

[Frankie-Xu]

Summary

• Statusline "not built" is now "no graph artifact", not "zero nodes".
• A successful graft build that produces an empty wiring.json (docs-only repos, skipped languages) renders as ◤ graft · 0 nodes / 0 edges · ✓ synced.
• Repos with no wiring.json still render ◤ graft · not built · run graft build.
• Non-empty graphs are unchanged.

Cause

As analyzed in #185: renderStatusline() treated nodeCount === 0 as never-built, and resolveStats() could not tell a legitimate empty graph from a missing one — both look like zero. graft build already succeeds (✓ wiring: 0 nodes ...); only the bar was lying.

Built is now artifact presence (wiring.json via readWiring()). renderStatusline only shows "not built" when stats are null. A 0-node cache without wiring is still missing, not empty-and-built.

Test plan

• node --import tsx --test test/claude-format.test.ts test/claude-statusline.test.ts test/claude-stats.test.ts (31/31)
• npm run build && npm test (882/882)
• Manual docs-only repo (README.md only, git init + commit, graft build):

# graft build
✓ wiring: 0 nodes (), 0 edges, 0 cards []

# statusline after that successful empty build
◤ graft · 0 nodes / 0 edges · ✓ synced

# control: same layout, never built (no wiring.json)
◤ graft · not built · run graft build

# control: this repo (non-empty graph, same bar style as before)
◤ graft · 1524 nodes / 4547 edges · ✓ synced

Closes #185

Made with Cursor

[github-actions]

🌱 graft blast radius

Nothing outside this diff depends on it. 1 area changed; no indexed dependents at depth 2.
Tests: 1 area updated its tests.

Test signal per changed area — 1 ✓

Reached = a node under a test path has a resolved edge into the changed symbol. It undercounts anything called indirectly — through a CLI, a spawned process or a dynamic import — so read a low ratio as “look here”, never as a coverage gate.

• ✓ Status Display — 2 of 2 reached · 2 test files changed here: test/claude-format.test.ts, test/claude-statusline.test.ts

_{graft blast · origin/main...HEAD · depth 2 · 4 changed files}

Open the interactive graph → — click an area to see its dependent symbols at file:line.

[shhdwi]

Verified locally on top of current main (clean merge; build clean).

Before/after (statusline line, ANSI-stripped):

• Missing graph (no wiring.json): ◤ graft · not built · run graft build — unchanged, still correct.
• Empty-but-built graph (docs-only repo, wiring.json with 0 nodes): OLD ◤ graft · not built · run graft build (the Statusline reports "not built" for a successfully-built but empty graph #185 bug) → NEW ◤ graft · 0 nodes / 0 edges · ✓ synced.

Fix is format.ts (nodeCount === 0 no longer forced into "not built") + resolveStats() returning null only when the artifact is genuinely absent. 3 new tests for the empty-graph case; claude-* 105/105. Fixes #185. Merging.