refactor(core): introduce InjectionService with source-aware injection and backend-native background completions (#22544)

packages/cli/src/test-utils/AppRig.tsx

@@ -624,7 +624,7 @@ export class AppRig {
   async addUserHint(hint: string) {
     if (!this.config) throw new Error('AppRig not initialized');
     await act(async () => {
-      this.config!.userHintService.addUserHint(hint);
+      this.config!.injectionService.addInjection(hint, 'user_steering');
     });
   }
 

packages/cli/src/ui/AppContainer.tsx

@@ -85,6 +85,7 @@ import {
   buildUserSteeringHintPrompt,
   logBillingEvent,
   ApiKeyUpdatedEvent,
+  type InjectionSource,
 } from '@google/gemini-cli-core';
 import { validateAuthMethod } from '../config/auth.js';
 import process from 'node:process';
@@ -1089,13 +1090,16 @@ Logging in with Google... Restarting Gemini CLI to continue.
   }, []);
 
   useEffect(() => {
-    const hintListener = (hint: string) => {
-      pendingHintsRef.current.push(hint);
+    const hintListener = (text: string, source: InjectionSource) => {
+      if (source !== 'user_steering') {
+        return;
+      }
+      pendingHintsRef.current.push(text);
       setPendingHintCount((prev) => prev + 1);
     };
-    config.userHintService.onUserHint(hintListener);
+    config.injectionService.onInjection(hintListener);
     return () => {
-      config.userHintService.offUserHint(hintListener);
+      config.injectionService.offInjection(hintListener);
     };
   }, [config]);
 
@@ -1259,7 +1263,7 @@ Logging in with Google... Restarting Gemini CLI to continue.
       if (!trimmed) {
         return;
       }
-      config.userHintService.addUserHint(trimmed);
+      config.injectionService.addInjection(trimmed, 'user_steering');
       // Render hints with a distinct style.
       historyManager.addItem({
         type: 'hint',

packages/cli/src/ui/commands/clearCommand.test.ts

@@ -51,7 +51,7 @@ describe('clearCommand', () => {
             fireSessionEndEvent: vi.fn().mockResolvedValue(undefined),
             fireSessionStartEvent: vi.fn().mockResolvedValue(undefined),
           }),
-          userHintService: {
+          injectionService: {
             clear: mockHintClear,
           },
         },

packages/cli/src/ui/commands/clearCommand.ts

@@ -30,7 +30,7 @@ export const clearCommand: SlashCommand = {
     }
 
     // Reset user steering hints
-    config?.userHintService.clear();
+    config?.injectionService.clear();
 
     // Start a new conversation recording with a new session ID
     // We MUST do this before calling resetChat() so the new ChatRecordingService