Add Antigravity as a usage source

[nuchareviews-beep]

Summary

• Adds Antigravity as a new usage source, alongside Codex, Claude Code, FX, Grok Agent, OpenCode, Pi, and Prime Agent.
• Antigravity is bridged into BB by a companion plugin (bb-plugin-antigravity-acp) that shells out to the local agy CLI per turn. agy has no session log of its own in a stable, parseable shape, so that bridge writes one JSONL line per turn to ~/.antigravity-acp/usage.jsonl, in the same kind: "generation" / fact shape this plugin already reads for FX — so this change reuses that existing parsing path (matches(), the inline host-scan branch, parseHostUsageAggregates) rather than introducing a new file format or a new top-level collector function.
• Threaded "antigravity" through AgentId, HostJsonAgentId, jsonAgentRoots, the AGENTS list, and the host-json-collector's file matcher + inline parser.

Why not push data in directly from a plugin?

I looked for an ingestion API (RPC/HTTP route) this plugin exposes for other plugins to report usage into, and didn't find one — it's read-only, parsing local logs itself. Adding a new local-log source felt more in keeping with the existing architecture than adding a new ingestion surface, so that's the shape this PR takes. Happy to go a different direction if you'd rather have an ingestion API instead.

Test plan

• npm test — all 67 tests pass (64 pre-existing + 3 new: a collectors.test.ts case, a host-json-collector.test.ts case, and a jsonAgentRoots case in server.test.ts)
• npx tsc --noEmit — clean
• Verified against a real log line produced by a live bb-plugin-antigravity-acp turn (not just synthetic fixtures) — confirmed it parses into a correct usage row before opening this PR

🤖 Generated with Claude Code

[MayankBansal12]

hey @nuchareviews-beep, thanks for raising the PR, will take a look and get it merged today!

[MayankBansal12]

opencode agent on behalf of mayank

Thanks for this — the approach of reusing the existing FX generation/fact JSONL parsing path is a good fit, and the wiring through AgentId, jsonAgentRoots, and the collector matcher looks clean.

One thing needs fixing before this can merge: syncAll in server.ts only runs collectors via explicit syncJsonAgent(...) calls (see lines ~580–587), and there's no call for "antigravity". As it stands, the AGENTS entry will show the filter option in the UI, but no sync will ever run for it — no usage rows and no sync-state row will be created. The new tests pass because they invoke scan() directly, which skips syncAll.

Please add a syncJsonAgent(bb, db, machine, home, "antigravity", collectorSettings, ...) call alongside the others in that Promise.all, plus a test that exercises it through syncAll. Happy to re-review after.

[MayankBansal12]

@nuchareviews-beep i don't use antigravity so couldn't verify the usage stats...please ensure you have tested on your end and if possible please attach a screenshot in PR