feat(antigravity): add Gemini 3.7 Flash models (#3286, #3281)

Add gemini-3.7-flash and its tiered high/medium/low variants to the
Antigravity and Gemini registries, with matching capabilities, pricing
and Antigravity quota tracking.

extractModel now recognises gemini-3.7-flash-tiered alongside 3.6 and
derives the version from the request, so thinkingLevel still maps to the
right tiered alias.

Closes #3286
Closes #3281

tests/unit/antigravity-quota-gemini-3.7.test.js

@@ -0,0 +1,61 @@
+import { describe, expect, it, vi, beforeEach } from "vitest";
+
+const proxyAwareFetch = vi.fn(async (url) => ({
+  ok: true,
+  status: 200,
+  json: async () => url.includes(":loadCodeAssist")
+    ? { cloudaicompanionProject: "project-1", currentTier: { name: "Pro" } }
+    : {
+        models: {
+          "gemini-3.7-flash-high": {
+            displayName: "Gemini 3.7 Flash (High)",
+            quotaInfo: { remainingFraction: 0.85, resetTime: "2026-08-25T12:00:00Z" },
+          },
+          "gemini-3.7-flash-medium": {
+            displayName: "Gemini 3.7 Flash (Medium)",
+            quotaInfo: { remainingFraction: 0.6, resetTime: "2026-08-25T12:00:00Z" },
+          },
+          "gemini-3.7-flash-low": {
+            displayName: "Gemini 3.7 Flash (Low)",
+            quotaInfo: { remainingFraction: 0.35, resetTime: "2026-08-25T12:00:00Z" },
+          },
+          "internal-model": {
+            displayName: "Internal",
+            isInternal: true,
+            quotaInfo: { remainingFraction: 0.5 },
+          },
+        },
+      },
+  text: async () => "{}",
+}));
+
+vi.mock("../../open-sse/utils/proxyFetch.js", () => ({
+  proxyAwareFetch,
+}));
+
+describe("Antigravity quota tracker: Gemini 3.7 Flash usage bars", () => {
+  beforeEach(() => proxyAwareFetch.mockClear());
+
+  it("returns Gemini 3.7 Flash tier quotas so the dashboard can render usage bars", async () => {
+    const { getAntigravityUsage } = await import("../../open-sse/services/usage/google.js");
+
+    const usage = await getAntigravityUsage("access-token", {});
+
+    expect(usage.quotas["gemini-3.7-flash-high"]).toMatchObject({
+      used: 150,
+      total: 1000,
+      remainingPercentage: 85,
+      displayName: "Gemini 3.7 Flash (High)",
+    });
+    expect(usage.quotas["gemini-3.7-flash-medium"]).toMatchObject({
+      used: 400,
+      total: 1000,
+      remainingPercentage: 60,
+    });
+    expect(usage.quotas["gemini-3.7-flash-low"]).toMatchObject({
+      used: 650,
+      total: 1000,
+      remainingPercentage: 35,
+    });
+  });
+});

tests/unit/gemini-3.7-antigravity.test.js

@@ -0,0 +1,36 @@
+import { describe, it, expect } from "vitest";
+import { getCapabilitiesForModel } from "../../open-sse/providers/capabilities.js";
+import antigravityRegistry from "../../open-sse/providers/registry/antigravity.js";
+import geminiRegistry from "../../open-sse/providers/registry/gemini.js";
+import { MODEL_PRICING } from "../../open-sse/providers/pricing.js";
+
+describe("Gemini 3.7 Flash Support & Config (#3286, #3281)", () => {
+  it("registers gemini-3.7-flash tiered models in antigravity provider registry", () => {
+    const agIds = antigravityRegistry.models.map(m => m.id);
+    expect(agIds).toContain("gemini-3.7-flash-high");
+    expect(agIds).toContain("gemini-3.7-flash-medium");
+    expect(agIds).toContain("gemini-3.7-flash-low");
+    expect(agIds).not.toContain("gemini-3.7-flash");
+  });
+
+  it("registers gemini-3.7-flash in gemini provider registry", () => {
+    const geminiIds = geminiRegistry.models.map(m => m.id);
+    expect(geminiIds).toContain("gemini-3.7-flash");
+  });
+
+  it("resolves capabilities correctly for gemini-3.7 models with official limits", () => {
+    const caps = getCapabilitiesForModel("antigravity", "gemini-3.7-flash-high");
+    expect(caps.vision).toBe(true);
+    expect(caps.reasoning).toBe(true);
+    expect(caps.thinkingFormat).toBe("gemini-level");
+    expect(caps.contextWindow).toBe(1048576);
+    expect(caps.maxOutput).toBe(65536);
+  });
+
+  it("defines pricing matching gemini-3.6-flash baseline", () => {
+    expect(MODEL_PRICING["gemini-3.7-flash"]).toEqual(MODEL_PRICING["gemini-3.6-flash"]);
+    expect(MODEL_PRICING["gemini-3.7-flash-high"]).toEqual(MODEL_PRICING["gemini-3.6-flash-high"]);
+    expect(MODEL_PRICING["gemini-3.7-flash-medium"]).toEqual(MODEL_PRICING["gemini-3.6-flash-medium"]);
+    expect(MODEL_PRICING["gemini-3.7-flash-low"]).toEqual(MODEL_PRICING["gemini-3.6-flash-low"]);
+  });
+});