fix: Implement secure licensing with grace periods

- Add 90-day offline grace period for licensed users
- Add 1-day offline grace period for trial users
- Conservative license deletion (only on explicit invalid/revoked)
- Unified 8-hour cache TTL for all users
- Optimize trial validation (check expiry before grace)
- Never delete licenses on network errors or grace expiry
- Protect user data with recovery paths for all blocked states

This ensures legitimate users can work offline for extended periods
while preventing license abuse. Licensed users won't lose access due
to temporary network issues or extended travel.

Author: moinulmoin

.gitignore

@@ -41,6 +41,6 @@ agent-reports
 
 notarized-build-*
 
-.claudedocs/
+claudedocs/
 
 agent-docs/