feat(insights): /usage-style profile + cost attribution; scanner perf overhaul

[Gnonymous]

Summary

Borrows two ideas from Claude Code's /usage and Claude Desktop's Overview, while keeping CodingBar's "100% local" promise — every new data point is derived from already-scanned RawRecords, no new I/O sources, no new network paths.

Ships in three layered slices:

Insights tab — all-time Profile

• 2×4 stat grid: sessions, messages, total tokens, active days, current/longest streak, peak hour, favorite model.
• GitHub-style 13-week contribution calendar (blue palette, 7 rows × 13 weeks).
• Fun-fact callout ("~N× Harry Potter") tied to lifetime tokens.
• Replaces the old weekday × hour heatmap on the Insights tab — the new calendar carries the same activity signal with more time depth.

Cost tab — usage attribution

Two new sections, both Claude-only (Codex carries no attribution tags and its tokens are deltas of a running total, not absolute prompt size), both range-aware and metric-aware so they follow the existing right-pill + cost/tokens toggle.

• By context size: ≤50k / 50–150k / >150k bands using the absolute prompt size from each request's usage block. Mirrors /usage's "what's contributing to your usage" lens; on this machine the >150k band came in at 53% of 30-day Claude spend.
• Skills / Subagents / Plugins / MCP servers tables: read straight from Claude Code's own attribution* fields on each assistant line with usage, so percentages are an exact group-and-sum — not a heuristic. Honest "% of usage" denominator = Claude total in range, so shares are independent and don't sum to 100 (most turns carry no attribution at all).

Scanner perf — boot peak RSS ~1.3 GB → ~75 MB

Before this branch a fresh launch on a 711 MB / 1623-file / 51k-record corpus would spike to ~1.3 GB resident before settling back to ~190 MB. After:

	before	after	delta
Boot peak RSS (.app)	~1.3 GB	~75 MB	-94%
Steady-state RSS (.app)	~190 MB	49–56 MB	-74%
Warm CLI dump peak	~190 MB	108 MB	-43%
Cache file size	18 MB JSON	6.86 MB binary plist	-62%

Three orthogonal fixes:

1. Per-line autoreleasepool in both scanners. JSONSerialization returns autoreleased NSDictionary/NSString trees; in a tight scan loop running inside a detached Task there's no natural pool drain, and intermediates pile up across files. Wrapping each line drains immediately.
2. Shared Scanner across Claude + Codex. Previously each provider instantiated its own Scanner and re-decoded the same cache file twice per Aggregator.run(). Now one Scanner is created in the aggregator and passed to both.
3. Cache format JSON → binary property list. PropertyListDecoder reads directly into the Swift struct without the giant intermediate NSDictionary tree that JSONDecoder builds via JSONSerialization. Cache file also shrinks ~62%. cacheVersion bumped 4 → 5 (forces one full rescan on next launch; pre-release so no user impact).

Privacy boundary

Unchanged. Two network paths only, both pre-existing: Claude/Codex quota GETs (TTL-cached, the user's own OAuth token) and a user-initiated GitHub releases GET. No telemetry, no log uploads.

Test plan

• swift build clean (debug + release)
• make test (--self-test) — ALL PASS
• --dump-json on real local corpus — profile (sessions=1398, activeDays=104, streak=32, peakHour=16, favorite=Opus 4.8), context attribution (>150k = 52/55/53% across today/7d/30d), usage attribution (workflow-subagent 14.2%, playwright MCP 10.7%, orchestration skill 4.8% on 30d) all match /usage-style numbers
• Insights tab dark + light rasterized via --render-panel — 2×4 grid + calendar + fun fact render correctly
• Cost tab dark/cost + light/tokens rasterized — both new sections follow range pill and metric toggle
• .app boot peak measured at 49–75 MB resident (down from ~1.3 GB)
• Cache file header inspected (bplist00 magic), size 6.86 MB
• New ProfileBuilder tests + new attribution-parsing test added to SmokeTests.swift
• CI XCTest run (only runnable in CI — needs Xcode toolchain that isn't on the local CLT)
• Regenerate docs/assets/panel-insights.png / panel-overview.png reference shots (left to a follow-up since docs/assets/*.png already had pre-existing uncommitted changes on this working tree)

🤖 Generated with Claude Code