Keep agent profile settings valid across providers (#3331)

* fix(app): keep profile modes scoped to providers

Applying a profile through sequential field setters allowed a provider change
to race mode persistence, poisoning modeless provider preferences with another
provider's mode. Apply profiles as one form transition and heal invalid
provider-scoped mode preferences when profiles are used.

* test(app): cover profile features across providers

packages/app/src/composer/agent-controls/mode.test.ts

@@ -20,7 +20,6 @@ describe("resolveAgentControlsMode", () => {
       resolveAgentControlsMode({
         providerDefinitions: [],
         selectedProvider: "codex",
-        onSelectProvider: () => undefined,
         modeOptions: [],
         selectedMode: "",
         onSelectMode: () => undefined,
@@ -34,6 +33,7 @@ describe("resolveAgentControlsMode", () => {
         thinkingOptions: [],
         selectedThinkingOptionId: "",
         onSelectThinkingOption: () => undefined,
+        onApplyAgentProfile: () => undefined,
       }),
     ).toBe("draft");
   });