batch3 T4 review polish: drop Stats hack, document cache race + total counting

- Drop unused Stats type import and its no-op suppression expression
- Comment getProjectFiles concurrent-miss race (benign, accepted)
- Comment findFiles deliberate post-limit counting (differs from grep)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/server/src/services/file_index.ts

@@ -15,6 +15,9 @@ interface CacheEntry {
 
 const cache = new Map<string, CacheEntry>(); // keyed by projectId
 
+// Concurrent calls with a cold/stale cache may both spawn rg. The result is
+// deterministic so they overwrite identically — no data corruption, just a
+// rare extra subprocess. Acceptable for single-user mode.
 export async function getProjectFiles(projectId: string, projectRoot: string): Promise<string[]> {
   const current = await snapMtimes(projectRoot);
   const cached = cache.get(projectId);

apps/server/src/services/file_ops.ts

@@ -1,7 +1,6 @@
 import { readFile, readdir, stat } from 'node:fs/promises';
 import { resolve, relative } from 'node:path';
 import { spawn } from 'node:child_process';
-import type { Stats } from 'node:fs';
 import { pathGuard, PathScopeError } from './path_guard.js';
 
 const MAX_FILE_BYTES = 5 * 1024 * 1024;
@@ -48,9 +47,6 @@ export interface FindFilesResult {
   truncated: boolean;
 }
 
-// Suppress unused import warning — Stats is part of the public API surface
-void (undefined as unknown as Stats);
-
 export async function listDir(projectRoot: string, relPath: string): Promise<ListDirResult> {
   const real = await pathGuard(projectRoot, relPath);
   const s = await stat(real);
@@ -224,6 +220,8 @@ export async function findFiles(
         const line = buf.slice(0, idx);
         buf = buf.slice(idx + 1);
         if (!line) continue;
+        // Keep counting after limit to report accurate `total` to the caller.
+        // grep kills early since the LLM doesn't need a total; this differs intentionally.
         total++;
         if (files.length < limit) {
           files.push(relative(projectRoot, line) || line);