[Bug]: shutdown timeout on large repos causes gob index corruption

[khaney64]

Bug Description

When running grepai watch on a large repository and stopping with Ctrl-C (the documented stop method), the shutdown process exceeds an internal timeout, resulting in a partially-written gob index file that cannot be loaded on next startup.

Steps to Reproduce

Steps to reproduce:

Run grepai index on a large repository (openclaw codebase, ~hundreds of files)
Run grepai watch — wait for Watching for changes... (Press Ctrl+C to stop)
Press Ctrl-C to stop
Observe shutdown output shows [STOPPED] - shutdown timeout
Run grepai watch again

Expected Behavior

Watch stops cleanly and the index is intact on next run.

Actual Behavior

[STOPPED] C:\development\ai\openclaw-code\openclaw - shutdown timeout

On next grepai watch:
[ERROR] C:\development\ai\openclaw-code\openclaw - failed to load index: failed to decode index: unexpected EOF
Error: failed to load index: failed to decode index: unexpected EOF

grepai Version

grepai version 0.35.0

Operating System

Windows

Embedding Provider

Ollama (nomic-embed-text)

Relevant Logs

Configuration

Checklist

• I have searched existing issues to avoid duplicates
• I am using the latest version of grepai