fix: resolve all 301 error handling anti-patterns across codebase

Systematic cleanup of every error handling anti-pattern detected by the
automated scanner. 289 issues fixed via code changes, 12 approved with
specific technical justifications.

Changes across 90 files:
- GENERIC_CATCH (141): Added instanceof Error type discrimination
- LARGE_TRY_BLOCK (82): Extracted helper methods to narrow try scope to ≤10 lines
- NO_LOGGING_IN_CATCH (65): Added logger/console calls for error visibility
- CATCH_AND_CONTINUE_CRITICAL_PATH (10): Added throw/return or approved overrides
- ERROR_STRING_MATCHING (2): Approved with rationale (no typed error classes)
- ERROR_MESSAGE_GUESSING (1): Replaced chained .includes() with documented pattern array
- PROMISE_CATCH_NO_LOGGING (1): Added logging to .catch() handler

Also fixes a detector bug where nested try/catch inside a catch block
corrupted brace-depth tracking, causing false positives.

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

src/services/smart-file-read/parser.ts

@@ -15,6 +15,7 @@ import { writeFileSync, readFileSync, mkdtempSync, rmSync, existsSync } from "no
 import { join, dirname } from "node:path";
 import { tmpdir } from "node:os";
 import { createRequire } from "node:module";
+import { logger } from "../../utils/logger.js";
 
 // CJS-safe require for resolving external packages at runtime.
 // In ESM: import.meta.url works. In CJS bundle (esbuild): __filename works.
@@ -160,6 +161,7 @@ export function loadUserGrammars(projectRoot: string): UserGrammarConfig {
     const content = readFileSync(configPath, "utf-8");
     rawConfig = JSON.parse(content);
   } catch {
+    // [ANTI-PATTERN IGNORED]: .claude-mem.json missing is the normal case for most projects
     userGrammarCache.set(projectRoot, EMPTY_USER_GRAMMAR_CONFIG);
     return EMPTY_USER_GRAMMAR_CONFIG;
   }
@@ -274,7 +276,9 @@ function resolveGrammarPath(language: string): string | null {
       const rootPkgPath = _require.resolve(pkg + "/package.json");
       const resolved = join(dirname(rootPkgPath), subdir);
       if (existsSync(join(resolved, "src"))) return resolved;
-    } catch { /* fall through */ }
+    } catch {
+      // [ANTI-PATTERN IGNORED]: grammar package not installed is expected for unsupported languages
+    }
     return null;
   }
 
@@ -282,6 +286,7 @@ function resolveGrammarPath(language: string): string | null {
     const packageJsonPath = _require.resolve(pkg + "/package.json");
     return dirname(packageJsonPath);
   } catch {
+    // [ANTI-PATTERN IGNORED]: grammar package not installed is expected for unsupported languages
     return null;
   }
 }
@@ -550,7 +555,9 @@ function getTreeSitterBin(): string {
       cachedBinPath = binPath;
       return binPath;
     }
-  } catch { /* fall through */ }
+  } catch {
+    // [ANTI-PATTERN IGNORED]: tree-sitter-cli not in node_modules is expected; falls back to PATH
+  }
 
   // Fallback: assume it's on PATH
   cachedBinPath = "tree-sitter";
@@ -585,7 +592,8 @@ function runBatchQuery(queryFile: string, sourceFiles: string[], grammarPath: st
   let output: string;
   try {
     output = execFileSync(bin, execArgs, { encoding: "utf-8", timeout: 30000, stdio: ["pipe", "pipe", "pipe"] });
-  } catch {
+  } catch (error) {
+    logger.debug('WORKER', `tree-sitter query failed for ${sourceFiles.length} file(s)`, undefined, error instanceof Error ? error : undefined);
     return new Map();
   }
 

src/services/smart-file-read/search.ts

@@ -13,6 +13,7 @@
 import { readFile, readdir, stat } from "node:fs/promises";
 import { join, relative } from "node:path";
 import { parseFilesBatch, formatFoldedView, loadUserGrammars, type FoldedFile } from "./parser.js";
+import { logger } from "../../utils/logger.js";
 
 const CODE_EXTENSIONS = new Set([
   ".js", ".jsx", ".ts", ".tsx", ".mjs", ".cjs",
@@ -78,7 +79,8 @@ async function* walkDir(dir: string, rootDir: string, maxDepth: number = 20, ext
   let entries;
   try {
     entries = await readdir(dir, { withFileTypes: true });
-  } catch {
+  } catch (error) {
+    logger.debug('WORKER', `walkDir: failed to read directory ${dir}`, undefined, error instanceof Error ? error : undefined);
     return; // permission denied, etc.
   }
 
@@ -114,7 +116,8 @@ async function safeReadFile(filePath: string): Promise<string | null> {
     if (content.slice(0, 1000).includes("\0")) return null;
 
     return content;
-  } catch {
+  } catch (error) {
+    logger.debug('WORKER', `safeReadFile: failed to read ${filePath}`, undefined, error instanceof Error ? error : undefined);
     return null;
   }
 }