perf(lsp): emit workspace-relative paths in definition/references

lsp_query printed absolute paths from URIToFile (e.g. the full
/Users/.../internal/... prefix repeated per result) while file_search and the
AST summary already relativize. On a find_references across many files that
~60-char root prefix repeats per file group — wasted tokens for the LLM
consumer. Extract a Server.relPath helper (dedups the AST summary's inline
block) and apply it to definition and references display paths; the absolute
path is kept where the file is actually re-read for previews.

Adds a relPath unit test (in-workspace relativized, out-of-workspace unchanged).

internal/server/features_test.go

@@ -213,6 +213,20 @@ func TestASTQuerySkipsDependencyDirs(t *testing.T) {
 	}
 }
 
+// TestRelPath verifies workspace-relative display paths (token saving) with a
+// safe fallback to the original path for anything outside the root.
+func TestRelPath(t *testing.T) {
+	srv, tmpDir := newFeaturesServer(t)
+	if got := srv.relPath(filepath.Join(tmpDir, "pkg", "a.go")); got != filepath.Join("pkg", "a.go") {
+		t.Errorf("in-workspace path should be relativized, got %q", got)
+	}
+	// Outside the workspace root → returned unchanged (never a ../ escape string).
+	outside := "/definitely/outside/x.go"
+	if got := srv.relPath(outside); got != outside {
+		t.Errorf("out-of-workspace path should be returned as-is, got %q", got)
+	}
+}
+
 // ---- Feature 3 (ast_query): pagination cursor ----
 
 // TestASTQueryFirstPageCursor is a strict regression guard: page 1 must emit a

internal/server/handlers_ast.go

@@ -263,15 +263,7 @@ func (s *Server) generateASTSummary(ctx context.Context, path string, content []
 
 	var sb strings.Builder
 
-	// Get relative path
-	relPath := path
-	if absPath, err := filepath.Abs(path); err == nil {
-		if rel, err := filepath.Rel(s.cfg.WorkspaceRoot, absPath); err == nil && !strings.HasPrefix(rel, "..") {
-			relPath = rel
-		}
-	}
-
-	fmt.Fprintf(&sb, "**%s** (%d lines, %s)\n\n", relPath, countLines(content), lang)
+	fmt.Fprintf(&sb, "**%s** (%d lines, %s)\n\n", s.relPath(path), countLines(content), lang)
 	sb.WriteString("Symbols:\n")
 
 	for _, sym := range symbols {
@@ -282,6 +274,18 @@ func (s *Server) generateASTSummary(ctx context.Context, path string, content []
 	return sb.String()
 }
 
+// relPath renders path relative to the workspace root for display, saving the
+// tokens an absolute path would cost. Falls back to the original path when it
+// can't be relativized (outside the root, or on error).
+func (s *Server) relPath(path string) string {
+	if absPath, err := filepath.Abs(path); err == nil {
+		if rel, err := filepath.Rel(s.cfg.WorkspaceRoot, absPath); err == nil && !strings.HasPrefix(rel, "..") {
+			return rel
+		}
+	}
+	return path
+}
+
 // symbolKindIcon returns an icon/prefix for a symbol kind.
 func symbolKindIcon(kind protocol.SymbolKind) string {
 	switch kind {

internal/server/handlers_lsp.go

@@ -181,7 +181,7 @@ func (s *Server) lspDefinition(ctx context.Context, file string, line, col int,
 
 	for _, loc := range locations {
 		filePath := lsp.URIToFile(loc.URI)
-		fmt.Fprintf(&output, "**%s:%d:%d**\n", filePath, loc.Range.Start.Line+1, loc.Range.Start.Character+1)
+		fmt.Fprintf(&output, "**%s:%d:%d**\n", s.relPath(filePath), loc.Range.Start.Line+1, loc.Range.Start.Character+1)
 
 		preview := s.readFilePreview(filePath, loc.Range.Start.Line+1, 3)
 		if preview != "" {
@@ -210,7 +210,9 @@ func (s *Server) lspReferences(ctx context.Context, file string, line, col int,
 	fileGroups := make(map[string][]lsp.Location)
 	fileOrder := make([]string, 0)
 	for _, loc := range locations {
-		filePath := lsp.URIToFile(loc.URI)
+		// Relativize for display; references are not re-read so the absolute
+		// path isn't needed downstream.
+		filePath := s.relPath(lsp.URIToFile(loc.URI))
 		if _, seen := fileGroups[filePath]; !seen {
 			fileOrder = append(fileOrder, filePath)
 		}