fix(hooks): add stdin timeout guard to prevent hook errors

The context monitor and statusline hooks wait for stdin 'end' event
before processing. On some platforms (Windows/Git Bash), the stdin pipe
may not close cleanly, causing the script to hang until Claude Code's
hook timeout kills it — surfacing as "PostToolUse:Read hook error" after
every tool call. Add a 3-second timeout that exits silently if stdin
doesn't complete, preventing the noisy error messages.

Closes #775

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

hooks/gsd-context-monitor.js

@@ -27,9 +27,14 @@ const STALE_SECONDS = 60;      // ignore metrics older than 60s
 const DEBOUNCE_CALLS = 5;      // min tool uses between warnings
 
 let input = '';
+// Timeout guard: if stdin doesn't close within 3s (e.g. pipe issues on
+// Windows/Git Bash), exit silently instead of hanging until Claude Code
+// kills the process and reports "hook error". See #775.
+const stdinTimeout = setTimeout(() => process.exit(0), 3000);
 process.stdin.setEncoding('utf8');
 process.stdin.on('data', chunk => input += chunk);
 process.stdin.on('end', () => {
+  clearTimeout(stdinTimeout);
   try {
     const data = JSON.parse(input);
     const sessionId = data.session_id;

hooks/gsd-statusline.js

@@ -8,9 +8,13 @@ const os = require('os');
 
 // Read JSON from stdin
 let input = '';
+// Timeout guard: if stdin doesn't close within 3s (e.g. pipe issues on
+// Windows/Git Bash), exit silently instead of hanging. See #775.
+const stdinTimeout = setTimeout(() => process.exit(0), 3000);
 process.stdin.setEncoding('utf8');
 process.stdin.on('data', chunk => input += chunk);
 process.stdin.on('end', () => {
+  clearTimeout(stdinTimeout);
   try {
     const data = JSON.parse(input);
     const model = data.model?.display_name || 'Claude';