chore: merge dev into v2 (#34317)

Co-authored-by: Brendan Allan <14191578+Brendonovich@users.noreply.github.com>
Co-authored-by: opencode-agent[bot] <opencode-agent[bot]@users.noreply.github.com>
Co-authored-by: Affan Ali <93028901+affanali2k3@users.noreply.github.com>
Co-authored-by: affanali2k3 <affanalikhanxx@gmail.com>
Co-authored-by: Frank <frank@anoma.ly>
Co-authored-by: opencode-agent[bot] <219766164+opencode-agent[bot]@users.noreply.github.com>
Co-authored-by: James Long <longster@gmail.com>
Co-authored-by: Aiden Cline <63023139+rekram1-node@users.noreply.github.com>
Co-authored-by: Jay V <air@live.ca>
Co-authored-by: Dax Raad <d@ironbay.co>
Co-authored-by: Aarav Sareen <96787824+arvsrn@users.noreply.github.com>
Co-authored-by: OpeOginni <107570612+OpeOginni@users.noreply.github.com>
Co-authored-by: Luke Parker <10430890+Hona@users.noreply.github.com>
Co-authored-by: Ben Guthrie <benjee.012@gmail.com>
Co-authored-by: Dax <mail@thdxr.com>
Co-authored-by: Filip <34747899+neriousy@users.noreply.github.com>

packages/opencode/test/provider/provider.test.ts

@@ -356,6 +356,17 @@ it.instance(
   { config: { model: "anthropic/claude-sonnet-4-20250514" } },
 )
 
+it.instance(
+  "defaultModel treats empty provider config as no allowlist",
+  Effect.gen(function* () {
+    yield* setProcessEnv("ANTHROPIC_API_KEY", "test-api-key")
+    const model = yield* Provider.use.defaultModel()
+    expect(model.providerID).toBeDefined()
+    expect(model.modelID).toBeDefined()
+  }),
+  { config: { provider: {} } },
+)
+
 it.instance(
   "defaultModel returns a typed error when config excludes every provider",
   Effect.gen(function* () {