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/transcripts/field-utils.ts

@@ -1,3 +1,4 @@
+import { logger } from '../../utils/logger.js';
 import type { FieldSpec, MatchRule, TranscriptSchema, WatchTarget } from './types.js';
 
 interface ResolveContext {
@@ -142,7 +143,8 @@ export function matchesRule(
     try {
       const regex = new RegExp(rule.regex);
       return regex.test(String(value ?? ''));
-    } catch {
+    } catch (error: unknown) {
+      logger.debug('WORKER', 'Invalid regex in match rule', { regex: rule.regex }, error instanceof Error ? error : undefined);
       return false;
     }
   }

src/services/transcripts/processor.ts

@@ -277,7 +277,8 @@ export class TranscriptEventProcessor {
     if (!(trimmed.startsWith('{') || trimmed.startsWith('['))) return value;
     try {
       return JSON.parse(trimmed);
-    } catch {
+    } catch (error: unknown) {
+      logger.debug('WORKER', 'Failed to parse JSON string', { length: trimmed.length }, error instanceof Error ? error : undefined);
       return value;
     }
   }
@@ -321,18 +322,19 @@ export class TranscriptEventProcessor {
     if (!workerReady) return;
 
     const lastAssistantMessage = session.lastAssistantMessage ?? '';
+    const requestBody = JSON.stringify({
+      contentSessionId: session.sessionId,
+      last_assistant_message: lastAssistantMessage,
+      platformSource: session.platformSource
+    });
 
     try {
       await workerHttpRequest('/api/sessions/summarize', {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
-        body: JSON.stringify({
-          contentSessionId: session.sessionId,
-          last_assistant_message: lastAssistantMessage,
-          platformSource: session.platformSource
-        })
+        body: requestBody
       });
-    } catch (error) {
+    } catch (error: unknown) {
       logger.warn('TRANSCRIPT', 'Summary request failed', {
         error: error instanceof Error ? error.message : String(error)
       });
@@ -352,22 +354,25 @@ export class TranscriptEventProcessor {
     const context = getProjectContext(cwd);
     const projectsParam = context.allProjects.join(',');
 
+    const contextUrl = `/api/context/inject?projects=${encodeURIComponent(projectsParam)}&platformSource=${encodeURIComponent(session.platformSource)}`;
+    const agentsPath = expandHomePath(watch.context.path ?? `${cwd}/AGENTS.md`);
+
+    let response: Awaited<ReturnType<typeof workerHttpRequest>>;
     try {
-      const response = await workerHttpRequest(
-        `/api/context/inject?projects=${encodeURIComponent(projectsParam)}&platformSource=${encodeURIComponent(session.platformSource)}`
-      );
-      if (!response.ok) return;
-
-      const content = (await response.text()).trim();
-      if (!content) return;
-
-      const agentsPath = expandHomePath(watch.context.path ?? `${cwd}/AGENTS.md`);
-      writeAgentsMd(agentsPath, content);
-      logger.debug('TRANSCRIPT', 'Updated AGENTS.md context', { agentsPath, watch: watch.name });
-    } catch (error) {
-      logger.warn('TRANSCRIPT', 'Failed to update AGENTS.md context', {
+      response = await workerHttpRequest(contextUrl);
+    } catch (error: unknown) {
+      logger.warn('TRANSCRIPT', 'Failed to fetch AGENTS.md context', {
         error: error instanceof Error ? error.message : String(error)
       });
+      return;
     }
+
+    if (!response.ok) return;
+
+    const content = (await response.text()).trim();
+    if (!content) return;
+
+    writeAgentsMd(agentsPath, content);
+    logger.debug('TRANSCRIPT', 'Updated AGENTS.md context', { agentsPath, watch: watch.name });
   }
 }

src/services/transcripts/watcher.ts

@@ -43,7 +43,8 @@ class FileTailer {
     let size = 0;
     try {
       size = statSync(this.filePath).size;
-    } catch {
+    } catch (error: unknown) {
+      logger.debug('WORKER', 'Failed to stat transcript file', { file: this.filePath }, error instanceof Error ? error : undefined);
       return;
     }
 
@@ -152,7 +153,8 @@ export class TranscriptWatcher {
           return globSync(pattern, { nodir: true, absolute: true });
         }
         return [inputPath];
-      } catch {
+      } catch (error: unknown) {
+        logger.debug('WORKER', 'Failed to stat watch path', { path: inputPath }, error instanceof Error ? error : undefined);
         return [];
       }
     }
@@ -180,7 +182,8 @@ export class TranscriptWatcher {
     if (offset === 0 && watch.startAtEnd && initialDiscovery) {
       try {
         offset = statSync(filePath).size;
-      } catch {
+      } catch (error: unknown) {
+        logger.debug('WORKER', 'Failed to stat file for startAtEnd offset', { file: filePath }, error instanceof Error ? error : undefined);
         offset = 0;
       }
     }
@@ -216,11 +219,19 @@ export class TranscriptWatcher {
     try {
       const entry = JSON.parse(line);
       await this.processor.processEntry(entry, watch, schema, sessionIdOverride ?? undefined);
-    } catch (error) {
-      logger.debug('TRANSCRIPT', 'Failed to parse transcript line', {
-        watch: watch.name,
-        file: basename(filePath)
-      }, error as Error);
+    } catch (error: unknown) {
+      if (error instanceof Error) {
+        logger.debug('TRANSCRIPT', 'Failed to parse transcript line', {
+          watch: watch.name,
+          file: basename(filePath)
+        }, error);
+      } else {
+        logger.warn('TRANSCRIPT', 'Failed to parse transcript line (non-Error thrown)', {
+          watch: watch.name,
+          file: basename(filePath),
+          error: String(error)
+        });
+      }
     }
   }