fix: preserve existing matched posts when running AI Match

The mergeMatches function was incorrectly dropping existing pending
matches that weren't in new AI results. Since AI matching only evaluates
queued posts (not already-evaluated ones), there's no overlap between
existing and new matches - they should simply be combined.

Removed the status !== 'pending' condition so all existing matched posts
are preserved regardless of their status.

Author: charlesjones-dev

src/background/matcher.ts

@@ -266,11 +266,10 @@ export function mergeMatches(
     }
   }
 
-  // Add any existing matches not in new results that haven't been acted on
+  // Add all remaining existing matches (not in new results)
+  // These should be preserved since they were already evaluated and matched
   for (const existing of existingMap.values()) {
-    if (existing.status !== 'pending') {
-      merged.push(existing);
-    }
+    merged.push(existing);
   }
 
   // Sort by score descending

tests/background/matcher.test.ts

@@ -217,7 +217,7 @@ describe('Matcher', () => {
       expect(merged[0].score).toBe(0.8); // Score should be updated
     });
 
-    it('should add new matches not in existing', () => {
+    it('should add new matches while keeping existing matches', () => {
       const existing = [
         createTestMatch({
           post: createTestPost({ id: 'post-1' }),
@@ -232,28 +232,35 @@ describe('Matcher', () => {
 
       const merged = mergeMatches(existing, newMatches);
 
-      expect(merged.length).toBe(1); // Only new matches by default
+      expect(merged.length).toBe(2); // Both existing and new matches should be kept
+      expect(merged.some((m) => m.post.id === 'post-1')).toBe(true);
       expect(merged.some((m) => m.post.id === 'post-2')).toBe(true);
     });
 
-    it('should keep non-pending existing matches', () => {
+    it('should keep existing matches regardless of status', () => {
       const existing = [
         createTestMatch({
           post: createTestPost({ id: 'post-1' }),
+          status: 'pending',
+        }),
+        createTestMatch({
+          post: createTestPost({ id: 'post-2' }),
           status: 'replied',
         }),
       ];
 
       const newMatches = [
         createTestMatch({
-          post: createTestPost({ id: 'post-2' }),
+          post: createTestPost({ id: 'post-3' }),
         }),
       ];
 
       const merged = mergeMatches(existing, newMatches);
 
+      expect(merged.length).toBe(3);
       expect(merged.some((m) => m.post.id === 'post-1')).toBe(true);
       expect(merged.some((m) => m.post.id === 'post-2')).toBe(true);
+      expect(merged.some((m) => m.post.id === 'post-3')).toBe(true);
     });
 
     it('should respect maxMatchedPosts limit', () => {