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/worker/http/routes/SettingsRoutes.ts

@@ -74,7 +74,8 @@ export class SettingsRoutes extends BaseRouteHandler {
       try {
         settings = JSON.parse(settingsData);
       } catch (parseError) {
-        logger.error('SETTINGS', 'Failed to parse settings file', { settingsPath }, parseError as Error);
+        const normalizedParseError = parseError instanceof Error ? parseError : new Error(String(parseError));
+        logger.error('HTTP', 'Failed to parse settings file', { settingsPath }, normalizedParseError);
         res.status(500).json({
           success: false,
           error: 'Settings file is corrupted. Delete ~/.claude-mem/settings.json to reset.'