fix: Improve Python resolution accuracy and context relevance

Eliminate cross-language false positives in name resolution and deprioritize
test files in context building. Benchmarked on a Python+Rust codebase where
37% of edges were false positives from Python built-in methods resolving to
Rust functions (e.g., list.extend → Rust extend).

Resolution fixes (index-time):
- Filter Python built-in type method calls (list.extend, dict.update, etc.)
- Filter bare Python built-in method names (append, extend, pop, keys, etc.)
- Add language boundary checks to matchMethodCall strategies 1, 2, and 3
- Penalize cross-language matches: -80 points in findBestMatch (was 0)
- Reduce confidence for single cross-language exact matches (0.5 vs 0.9)
- Prefer same-language candidates in matchFuzzy

Context relevance fixes (query-time):
- Add isTestFile() utility detecting test files across Python/JS/TS/Go/Rust/Java
- Deprioritize test files in scorePathRelevance (-15 penalty)
- Reduce test file scores to 30% in context builder result merging
- Both skip deprioritization when query mentions "test" or "spec"

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/search/query-utils.ts

@@ -79,9 +79,45 @@ export function scorePathRelevance(filePath: string, query: string): number {
     else if (pathLower.includes(term)) score += 3;
   }
 
+  // Deprioritize test files unless the query is explicitly about tests
+  const queryLower = query.toLowerCase();
+  const isTestQuery = queryLower.includes('test') || queryLower.includes('spec');
+  if (!isTestQuery && isTestFile(filePath)) {
+    score -= 15;
+  }
+
   return score;
 }
 
+/**
+ * Check if a file path looks like a test file
+ */
+export function isTestFile(filePath: string): boolean {
+  const lower = filePath.toLowerCase();
+  const fileName = path.basename(lower);
+
+  // Common test file patterns
+  return (
+    fileName.startsWith('test_') ||
+    fileName.startsWith('test.') ||
+    fileName.endsWith('.test.ts') ||
+    fileName.endsWith('.test.js') ||
+    fileName.endsWith('.test.tsx') ||
+    fileName.endsWith('.test.jsx') ||
+    fileName.endsWith('.spec.ts') ||
+    fileName.endsWith('.spec.js') ||
+    fileName.endsWith('_test.go') ||
+    fileName.endsWith('_test.py') ||
+    fileName.endsWith('_test.rs') ||
+    fileName.endsWith('Tests.java') ||
+    fileName.endsWith('Test.java') ||
+    lower.includes('/tests/') ||
+    lower.includes('/test/') ||
+    lower.includes('/__tests__/') ||
+    lower.includes('/spec/')
+  );
+}
+
 /**
  * Kind-based bonus for search ranking
  * Functions and classes are typically more relevant than variables/imports
@@ -91,10 +127,10 @@ export function kindBonus(kind: Node['kind']): number {
     function: 10,
     method: 10,
     class: 8,
-    interface: 7,
+    interface: 9,
     type_alias: 6,
     struct: 6,
-    trait: 6,
+    trait: 9,
     enum: 5,
     component: 8,
     route: 9,
@@ -108,7 +144,7 @@ export function kindBonus(kind: Node['kind']): number {
     parameter: 0,
     namespace: 4,
     file: 0,
-    protocol: 6,
+    protocol: 9,
     enum_member: 3,
   };
   return bonuses[kind] ?? 0;