fix: replace 40+ silent catch blocks with debug logging

Every empty catch {} in sidepanel.js, sidebar-agent.ts now logs with
[gstack sidebar] or [sidebar-agent] prefix. Chat poll 401s, stop agent,
tab poll, clear chat, SSE parse, refs fetch, stream JSON parse, queue
read/parse, process kill — all now visible in console.

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

browse/src/sidebar-agent.ts

@@ -30,7 +30,8 @@ function getGitRoot(): string | null {
   try {
     const { execSync } = require('child_process');
     return execSync('git rev-parse --show-toplevel', { encoding: 'utf-8', stdio: ['pipe', 'pipe', 'pipe'] }).trim();
-  } catch {
+  } catch (err: any) {
+    console.debug('[sidebar-agent] Not in a git repo:', err.message);
     return null;
   }
 }
@@ -74,7 +75,8 @@ async function refreshToken(): Promise<string | null> {
     const data = JSON.parse(fs.readFileSync(stateFile, 'utf-8'));
     authToken = data.token || null;
     return authToken;
-  } catch {
+  } catch (err: any) {
+    console.error('[sidebar-agent] Failed to refresh auth token:', err.message);
     return null;
   }
 }
@@ -234,7 +236,10 @@ async function askClaude(queueEntry: any): Promise<void> {
 
     // Validate cwd exists — queue may reference a stale worktree
     let effectiveCwd = cwd || process.cwd();
-    try { fs.accessSync(effectiveCwd); } catch { effectiveCwd = process.cwd(); }
+    try { fs.accessSync(effectiveCwd); } catch (err: any) {
+      console.warn('[sidebar-agent] Worktree path inaccessible, falling back to cwd:', effectiveCwd, err.message);
+      effectiveCwd = process.cwd();
+    }
 
     const proc = spawn('claude', claudeArgs, {
       stdio: ['pipe', 'pipe', 'pipe'],
@@ -264,7 +269,9 @@ async function askClaude(queueEntry: any): Promise<void> {
       buffer = lines.pop() || '';
       for (const line of lines) {
         if (!line.trim()) continue;
-        try { handleStreamEvent(JSON.parse(line), tid); } catch {}
+        try { handleStreamEvent(JSON.parse(line), tid); } catch (err: any) {
+          console.error(`[sidebar-agent] Tab ${tid}: Failed to parse stream line:`, line.slice(0, 100), err.message);
+        }
       }
     });
 
@@ -275,7 +282,9 @@ async function askClaude(queueEntry: any): Promise<void> {
 
     proc.on('close', (code) => {
       if (buffer.trim()) {
-        try { handleStreamEvent(JSON.parse(buffer), tid); } catch {}
+        try { handleStreamEvent(JSON.parse(buffer), tid); } catch (err: any) {
+          console.error(`[sidebar-agent] Tab ${tid}: Failed to parse final buffer:`, buffer.slice(0, 100), err.message);
+        }
       }
       const doneEvent: Record<string, any> = { type: 'agent_done' };
       if (code !== 0 && stderrBuffer.trim()) {
@@ -300,7 +309,9 @@ async function askClaude(queueEntry: any): Promise<void> {
     // Timeout (default 300s / 5 min — multi-page tasks need time)
     const timeoutMs = parseInt(process.env.SIDEBAR_AGENT_TIMEOUT || '300000', 10);
     setTimeout(() => {
-      try { proc.kill(); } catch {}
+      try { proc.kill(); } catch (killErr: any) {
+        console.warn(`[sidebar-agent] Tab ${tid}: Failed to kill timed-out process:`, killErr.message);
+      }
       const timeoutMsg = stderrBuffer.trim()
         ? `Timed out after ${timeoutMs / 1000}s\nstderr: ${stderrBuffer.trim().slice(-500)}`
         : `Timed out after ${timeoutMs / 1000}s`;
@@ -317,14 +328,20 @@ async function askClaude(queueEntry: any): Promise<void> {
 function countLines(): number {
   try {
     return fs.readFileSync(QUEUE, 'utf-8').split('\n').filter(Boolean).length;
-  } catch { return 0; }
+  } catch (err: any) {
+    console.error('[sidebar-agent] Failed to read queue file:', err.message);
+    return 0;
+  }
 }
 
 function readLine(n: number): string | null {
   try {
     const lines = fs.readFileSync(QUEUE, 'utf-8').split('\n').filter(Boolean);
     return lines[n - 1] || null;
-  } catch { return null; }
+  } catch (err: any) {
+    console.error(`[sidebar-agent] Failed to read queue line ${n}:`, err.message);
+    return null;
+  }
 }
 
 async function poll() {
@@ -337,7 +354,10 @@ async function poll() {
     if (!line) continue;
 
     let entry: any;
-    try { entry = JSON.parse(line); } catch { continue; }
+    try { entry = JSON.parse(line); } catch (err: any) {
+      console.warn(`[sidebar-agent] Skipping malformed queue entry at line ${lastLine}:`, line.slice(0, 80), err.message);
+      continue;
+    }
     if (!entry.message && !entry.prompt) continue;
 
     const tid = entry.tabId ?? 0;