feat(quota): collect weekly quota via retrieveUserQuotaSummary

[FlintyLemming]

Note: Backend-only. This PR implements weekly quota collection, persistence, and API exposure only. The frontend display is not implemented in this PR — I couldn't settle on the UI design (the weekly quota is grouped by model family rather than per-model, which doesn't map cleanly onto the existing per-model progress bars), so I'm leaving the UI for a follow-up. The data is fully available via the HTTP API for anyone who wants to consume it now.

Summary

Antigravity now exposes a weekly quota alongside the existing 5-hour quota per model group (e.g. "Gemini Models", "Claude and GPT models"). This PR collects that data from the upstream retrieveUserQuotaSummary endpoint, persists it to account files, and exposes it through the HTTP API.

Background

The fetchAvailableModels endpoint only returns a single per-model 5h quota window. The weekly quota is served by a separate endpoint discovered via network inspection of the official client:

POST /v1internal:retrieveUserQuotaSummary
Body: { "project": "<project_id>" }

It returns grouped buckets, each carrying both a weekly and a 5h window. The 5h values returned here are consistent with fetchAvailableModels (e.g. Gemini 0.9545 → 95%, Claude/GPT 0.7015 → 70%), confirming they are complementary rather than conflicting.

Changes

File	Change
src-tauri/src/models/quota.rs	Add QuotaBucket, QuotaGroup structs; add optional quota_groups field to QuotaData (#[serde(default)] for backward compat)
src-tauri/src/models/mod.rs	Re-export the new types
src-tauri/src/modules/quota.rs	Add fetch_quota_summary() calling retrieveUserQuotaSummary (3-endpoint fallback, best-effort — returns None on failure so the primary 5h quota is never blocked); embed it in fetch_quota_with_cache so all 10+ callers benefit automatically
src-tauri/src/proxy/server.rs	Expose quota_groups through GET /accounts and GET /accounts/:id via QuotaGroupDto/QuotaBucketDto
src/types/account.ts	Sync TypeScript types (QuotaBucket, QuotaGroup)
docker/Dockerfile.backend.localdist	Fix: add missing BoringSSL build deps (cmake, golang-go, clang, ninja-build, etc.) and COPY dist to the backend-builder stage

Design decisions

• Best-effort: if the weekly endpoint fails, the 5h quota is still returned normally. quota_groups is simply None and omitted from the JSON via #[serde(skip_serializing_if = "Option::is_none")].
• Zero-intrusion: no changes to fetch_quota_with_retry, persistence logic, or any UI component. No new Tauri command.
• Backward compatible: old account files without quota_groups deserialize fine (serde(default)).

Proof it works

GET /api/accounts/:id/quota on a Docker build from this branch:

Response (truncated, click to expand)

{
  "models": [
    { "name": "gemini-2.5-pro", "percentage": 95, "reset_time": "2026-06-16T07:43:38Z", "display_name": "Gemini 2.5 Pro", "..." : "..." },
    { "name": "claude-sonnet-4-6", "percentage": 70, "reset_time": "2026-06-16T07:26:50Z", "display_name": "Claude Sonnet 4.6 (Thinking)", "..." : "..." },
    { "name": "gpt-oss-120b-medium", "percentage": 70, "reset_time": "2026-06-16T07:26:50Z", "display_name": "GPT-OSS 120B (Medium)", "..." : "..." }
  ],
  "last_updated": 1781592425,
  "subscription_tier": "Google AI Pro",
  "model_forwarding_rules": { "gemini-3.1-pro-high": "gemini-pro-agent" },
  "quota_groups": [
    {
      "display_name": "Gemini Models",
      "description": "Models within this group: Gemini Flash, Gemini Pro",
      "buckets": [
        {
          "bucket_id": "gemini-weekly",
          "window": "weekly",
          "remaining_fraction": 0.99242574,
          "reset_time": "2026-06-23T02:43:38Z",
          "display_name": "Weekly Limit",
          "description": "You have used some of your weekly limit, it will fully refresh in 6 days, 19 hours."
        },
        {
          "bucket_id": "gemini-5h",
          "window": "5h",
          "remaining_fraction": 0.9545545,
          "reset_time": "2026-06-16T07:43:38Z",
          "display_name": "Five Hour Limit",
          "description": "You have used some of your 5-hour limit, it will fully refresh in 56 minutes."
        }
      ]
    },
    {
      "display_name": "Claude and GPT models",
      "description": "Models within this group: Claude Opus, Claude Sonnet, GPT-OSS",
      "buckets": [
        {
          "bucket_id": "3p-weekly",
          "window": "weekly",
          "remaining_fraction": 0.6558833,
          "reset_time": "2026-06-18T03:29:41Z",
          "display_name": "Weekly Limit",
          "description": "You have used some of your weekly limit, it will fully refresh in 1 day, 20 hours."
        },
        {
          "bucket_id": "3p-5h",
          "window": "5h",
          "remaining_fraction": 0.7015412,
          "reset_time": "2026-06-16T07:26:50Z",
          "display_name": "Five Hour Limit",
          "description": "You have used some of your 5-hour limit, it will fully refresh in 39 minutes."
        }
      ]
    }
  ]
}

Data consistency check — the 5h values from quota_groups match the per-model percentages in models:

Group	quota_groups 5h remaining_fraction	models percentage
Gemini	0.9545545	95% ✅
Claude & GPT	0.7015412	70% ✅

The weekly reset times (6d19h, 1d20h) are sliding windows, matching the behavior shown in the official Antigravity client.

Commits

• feat(quota): add weekly quota collection via retrieveUserQuotaSummary
• fix(docker): add missing build deps for BoringSSL in localdist Dockerfile
• fix: resolve compile errors and missing dist in localdist Dockerfile