Add Grok Build as a local runtime adapter

[ascendedent]

Grok Build already keeps session evidence under ~/.grok/sessions, but Token Meter did not discover it. This adds a read-only Grok runtime so those sessions show up with the other local agents.

What changed

• Discover owned session directories under GROK_HOME (default ~/.grok).
• Tokens and cache counts come from usage.json when Grok has persisted them. Cost is the Grok-recorded local estimate, not a Token Meter price table.
• Tool names, outcomes, and turn timing come from events.jsonl.
• Sessions without usage.json stay listed, with tokens and cost unavailable instead of a fake zero.
• Titles are generic. chat_history.jsonl, generated titles, and message content are not imported.
• Grok sessions cannot be deleted from Token Meter.
• Spend, budgets, and the runtime catalog pick Grok up through the existing registry.

Local secret files (auth.json, credentials, chrome-profile/, copied ~/.grok trees) are gitignored so they cannot be committed from a checkout.

[bhavsarpratik]

Thanks for adding Grok Build support and for keeping prompt and chat content out of the public projection.

We reviewed the current head (3edca5d) and are holding the merge for now. The next revision should:

• use Grok Build’s documented 1e10 cost ticks per USD instead of 1e9;
• treat zero, costIsPartial, and usageIsIncomplete cost evidence as unavailable rather than free or complete; and
• add fixtures and regression tests for the official scale and incomplete-cost cases.

Once the head is updated, we’ll rerun the provider-parsing, pricing, privacy, and runtime checks and get back to you soon.

— Pratik's agent

[ascendedent]

Thanks for the cost-scale catch. Head is now 169c5af.

• costUsdTicks converts at Grok Build’s documented 1e10 ticks per USD (was 1e9).
• Zero ticks, costIsPartial, and usageIsIncomplete keep cost unavailable instead of a measured free or complete session. Token counts stay measured when present.
• Tests cover the official scale (1e10 ticks → $1.00) and the zero / partial / incomplete cases.

Prompt and chat content remain out of the public projection. Ready for the provider-parsing and pricing checks on this head.