quota: opencode quota subcommand + per-provider quota functions

Program tracker: developing-today/code#6125 (Drew's order 2026-11-05 01:25 CST — the opencode quota subcommand becomes the ONLY producer of quota readings for the gatherer, the Supabase recorder, and every dashboard).

Today the fork has no quota subcommand and no provider quota function; quota is read by the OpenChamber module (packages/web/server/lib/quota in the openchamber repo) imported in-process by the laptop gatherer. Port those fetchers' wire behavior into the providers that own the credentials, behind one CLI subcommand emitting the module's existing result shape ({providerId, ok, configured, usage.windows{usedPercent, resetAt, valueLabel}, fetchedAt, error, planLabel, credentialId}).

Per-provider checklist (deployed pools):

• antigravity-direct (fork antigravity provider)
• mistral — incl. admin console budget read (billing.budget; API $15 + Vibe $150 dollar windows; cookie auth)
• claude (claude-code credentials)
• codex/openai (both ChatGPT accounts)
• opendesign
• cline-pass
• command-code (plan read, never balance)
• deepseek
• opencode-go (per credential)
• meta — portal-API read per fix(quota-plane): Meta percentage read — restore portal-API fetcher (subscription-quota) as the gatherer's source developing-today/code#6079 design, implemented provider-side
• turso — built-in fetcher in the subcommand (org usage API)
• groq — implement if a first-party quota surface exists; otherwise an explicit no-quota-surface class with evidence on code#6125
• CLI: opencode quota [--json] [PROVIDER ...] [--all]; skips disabled_providers unless --all/named; non-zero exit iff a requested provider has no successful result

vibe-direct's own provider quota is owned by the vibe lane — requirement + acceptance on #1709 (the mistral console read above still surfaces the Vibe budget figures through the subcommand).

Acceptance: live opencode quota --json covering every pool, Mistral dollar figures matching console truth (API $0.47/$15, Vibe $0.04/$150 at filing time).