perf(desktop): reduce Windows startup I/O and blocking checks
- Cache source hashes with metadata validation that detects source edits.
- Skip Node/npm checks when launching an up-to-date packaged app.
- Drain packaged console output into asynchronous rotating logs.
- Query gateway task state through COM without loading ScheduledTasks.
- Validate renderer assets using Vite's manifest, retaining torn-bundle
detection and the legacy fallback.
Add regression coverage for cache invalidation, console draining,
toolchain-free launches, gateway probing, and renderer validation.
Validation: 98 Python tests and 19 renderer tests passed.
db63214c7b