feat: Enhance symbol search with co-location boosting and receiver type support

Improves search accuracy by boosting results when multiple query symbols appear in the same file, addressing cases where common names like "run" return too many results. Adds Go method receiver type extraction to qualified names for better searchability (e.g., "scrapeLoop.run"). Optimizes database queries with two-pass approach to handle distinctive vs common symbol names efficiently.

src/context/index.ts

@@ -291,10 +291,36 @@ export class ContextBuilder {
     let exactMatches: SearchResult[] = [];
     if (symbolsFromQuery.length > 0) {
       try {
+        // Get more results so we can apply co-location boosting before trimming
         exactMatches = this.queries.findNodesByExactName(symbolsFromQuery, {
-          limit: Math.ceil(opts.searchLimit * 2), // Get more since we'll merge
+          limit: Math.ceil(opts.searchLimit * 5),
           kinds: opts.nodeKinds && opts.nodeKinds.length > 0 ? opts.nodeKinds : undefined,
         });
+
+        // Co-location boost: when multiple extracted symbols appear in the same file,
+        // those results are much more likely to be what the user is looking for.
+        // E.g., "scrapeLoop" + "run" both in scrape/scrape.go → boost both.
+        if (exactMatches.length > 1) {
+          // Build a map of files → how many distinct symbol names matched in that file
+          const fileSymbolCounts = new Map<string, Set<string>>();
+          for (const r of exactMatches) {
+            const names = fileSymbolCounts.get(r.node.filePath) || new Set();
+            names.add(r.node.name.toLowerCase());
+            fileSymbolCounts.set(r.node.filePath, names);
+          }
+          // Boost results in files where multiple query symbols co-occur
+          exactMatches = exactMatches.map(r => {
+            const symbolCount = fileSymbolCounts.get(r.node.filePath)?.size || 1;
+            return {
+              ...r,
+              score: symbolCount > 1 ? r.score + (symbolCount - 1) * 20 : r.score,
+            };
+          });
+          exactMatches.sort((a, b) => b.score - a.score);
+        }
+
+        // Trim back to reasonable size
+        exactMatches = exactMatches.slice(0, Math.ceil(opts.searchLimit * 2));
         logDebug('Exact symbol matches', { count: exactMatches.length });
       } catch (error) {
         logDebug('Exact symbol lookup failed', { error: String(error) });