## Summary
Two-part fix for #2411 — Windows embedded PostgreSQL backends dying with
exception `0xC0000142` and taking the whole dashboard down.
### 1. Crash hardening + recovery (FN-8522)
- Child-only native `PATH` hardening so forked backends can always
resolve their runtime DLLs.
- Non-blocking `.pgrunner` log monitoring (shared read), eliminating the
self-inflicted ~30s `sharing violation` retry window at boot.
- Detection of the ordered 0xC0000142 shutdown sequence with a single
automatic restart of owned clusters on their resolved port, plus
operator diagnostics.
### 2. Platform-aware `max_connections` default (follow-up from
[operator
report](https://github.com/Runfusion/Fusion/issues/2411#issuecomment-5054900702))
On Windows every PostgreSQL connection is a separate process; the
embedded cluster's unconfigured `max_connections=500` cap lets backend
spawn bursts exhaust the non-interactive desktop heap, which kills
forked backends with exactly `0xC0000142`. The reporter confirmed
stability after lowering the cap.
- `embeddedPostgresMaxConnections` is now schema-unset so the server can
distinguish "operator never set it" from an explicit choice
(`getSettings()` merges schema defaults, which previously pinned 500
unconditionally and made the runtime fallback dead code).
- New `resolveEmbeddedMaxConnections()` resolves the unset default
platform-aware: **150 on win32, 500 elsewhere**. Explicit settings are
honored on every platform, clamped to [32, 2000] as before.
- Settings UI renders the cap empty ("auto") with platform-aware help
copy across all six locales.
- Fixed a latent reset bug this exposed: global "Reset this menu" wrote
`undefined` for undefined-default keys, which JSON serialization drops —
the stored value silently survived reset. Now uses null-as-delete.
## Testing
- New unit tests for `resolveEmbeddedMaxConnections` (platform defaults,
clamping, non-integer handling).
- Updated settings-defaults, default-descriptions, and SettingsModal
tests; embedded lifecycle + recovery coverage from FN-8522.
- `@fusion/core` builds clean; changesets included for both parts.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
