fix(providers): suppress retired Copilot Gemini models (#9103)

Validated in local merge-train (devbox-vm-06-dev002) @ combined-tip (FAST gates: typecheck/complexity/cognitive/changelog/vitest — only pre-existing audit.test.ts flake). Evidence: /home/diegosouzapw/dev/proxys/OmniRoute/.claude/worktrees/merge-train-20260805-222248-suite.log

tests/unit/github-copilot-retired-models.test.ts

@@ -0,0 +1,95 @@
+import test, { after, before } from "node:test";
+import assert from "node:assert/strict";
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+
+const TEST_DATA_DIR = fs.mkdtempSync(path.join(os.tmpdir(), "omniroute-copilot-retired-"));
+process.env.DATA_DIR = TEST_DATA_DIR;
+
+const core = await import("../../src/lib/db/core.ts");
+const modelsDb = await import("../../src/lib/db/models.ts");
+const providersDb = await import("../../src/lib/db/providers.ts");
+
+before(() => {
+  core.resetDbInstance();
+});
+
+after(() => {
+  core.resetDbInstance();
+  fs.rmSync(TEST_DATA_DIR, { recursive: true, force: true });
+});
+
+test("GitHub Copilot sync rejects retired Gemini models", async () => {
+  await modelsDb.replaceSyncedAvailableModelsForConnection("github", "copilot-current", [
+    { id: "gemini-2.5-pro", name: "Gemini 2.5 Pro" },
+    { id: "gemini-3-flash", name: "Gemini 3 Flash" },
+    { id: "gemini-3-flash-preview", name: "Gemini 3 Flash Preview" },
+    { id: "gemini-3.6-flash", name: "Gemini 3.6 Flash" },
+  ]);
+
+  const ids = (await modelsDb.getSyncedAvailableModels("github")).map((model) => model.id);
+  assert.deepEqual(ids, ["gemini-3.6-flash"]);
+});
+
+test("GitHub Copilot readers hide retired models from legacy synced caches", async () => {
+  const db = core.getDbInstance();
+  db.prepare(
+    "INSERT INTO key_value (namespace, key, value) VALUES ('syncedAvailableModels', ?, ?)"
+  ).run(
+    "github:copilot-legacy",
+    JSON.stringify([
+      { id: "gemini-2.5-pro", name: "Gemini 2.5 Pro" },
+      { id: "gemini-3-flash-preview", name: "Gemini 3 Flash" },
+      { id: "gemini-3.6-flash", name: "Gemini 3.6 Flash" },
+    ])
+  );
+
+  const connectionIds = (
+    await modelsDb.getSyncedAvailableModelsForConnection("github", "copilot-legacy")
+  ).map((model) => model.id);
+  const providerIds = (await modelsDb.getSyncedAvailableModels("github")).map((model) => model.id);
+  const allProviderIds = (await modelsDb.getAllSyncedAvailableModels()).github.map(
+    (model) => model.id
+  );
+
+  assert.deepEqual(connectionIds, ["gemini-3.6-flash"]);
+  assert.deepEqual(providerIds, ["gemini-3.6-flash"]);
+  assert.deepEqual(allProviderIds, ["gemini-3.6-flash"]);
+});
+
+test("provider inference does not route retired Gemini models to GitHub Copilot", async () => {
+  const connection = await providersDb.createProviderConnection({
+    provider: "github",
+    authType: "oauth",
+    name: "copilot-retired-routing",
+    accessToken: "github-test-token",
+    isActive: true,
+    testStatus: "active",
+  });
+  const db = core.getDbInstance();
+  db.prepare(
+    "INSERT INTO key_value (namespace, key, value) VALUES ('syncedAvailableModels', ?, ?)"
+  ).run(
+    `github:${connection.id}`,
+    JSON.stringify([
+      { id: "gemini-2.5-pro", name: "Gemini 2.5 Pro" },
+      { id: "gemini-3.6-flash", name: "Gemini 3.6 Flash" },
+    ])
+  );
+
+  assert.deepEqual(await modelsDb.getActiveProvidersWithSyncedModel("gemini-2.5-pro"), []);
+  assert.deepEqual(await modelsDb.getActiveProvidersWithSyncedModel("gemini-3.6-flash"), [
+    "github",
+  ]);
+});
+
+test("retirement remains scoped to GitHub Copilot", async () => {
+  await modelsDb.replaceSyncedAvailableModelsForConnection("gemini", "gemini-direct", [
+    { id: "gemini-2.5-pro", name: "Gemini 2.5 Pro" },
+    { id: "gemini-3-flash", name: "Gemini 3 Flash" },
+  ]);
+
+  const ids = (await modelsDb.getSyncedAvailableModels("gemini")).map((model) => model.id);
+  assert.deepEqual(ids, ["gemini-2.5-pro", "gemini-3-flash"]);
+});