This commit addresses 4 P1 important issues and 1 P2 optimization in infrastructure components:
**P1-1: Missing Panic Recovery in Discovery Service** (service.go:172-195, 499-542)
- **Problem**: No panic recovery in Start(), ForceRefresh(), SetSubnet() goroutines
- **Impact**: Silent service death if scan panics, broken discovery with no monitoring
- **Fix**:
- Wrapped initial scan goroutine with defer/recover (lines 172-182)
- Wrapped scanLoop goroutine with defer/recover (lines 185-195)
- Wrapped ForceRefresh scan with defer/recover (lines 499-509)
- Wrapped SetSubnet scan with defer/recover (lines 532-542)
- All log panics with stack traces for debugging
**P1-2: Missing Panic Recovery in Config Watcher Callback** (watcher.go:546-556)
- **Problem**: User-provided onMockReload callback could panic and crash watcher
- **Impact**: Panicking callback kills watcher goroutine, no config updates
- **Fix**: Wrapped callback invocation with defer/recover and stack trace logging
**P1-3: Session Store Stop() Using Send Instead of Close** (session_store.go:16-84)
- **Problem**: Stop() used channel send which blocks if nobody reads
- **Impact**: Stop() hangs if backgroundWorker already exited
- **Fix**:
- Added sync.Once field stopOnce (line 22)
- Changed Stop() to use close() within stopOnce.Do() (lines 80-84)
- Prevents double-close panic and ensures all readers are signaled
**P2-1: Backup Cleanup Inefficient O(n²) Sort** (persistence.go:1424-1427)
- **Problem**: Bubble sort used to sort backups by modification time
- **Impact**: Inefficient for large backup counts (>100 files)
- **Fix**:
- Replaced bubble sort with sort.Slice() using O(n log n) algorithm
- Added "sort" import (line 9)
- Maintains same oldest-first ordering for deletion logic
All fixes add defensive programming without changing external behavior. Panic recovery ensures services continue operating even with bugs, while optimization reduces cleanup time for backup-heavy environments.