Health checks that wait for slow starts

If your app does real work before it's ready — database migrations, a cache warm, loading a model — it no longer has to race a fixed deadline.

Set the window in percher.toml, in seconds:

``toml [checks.health] initial_delay = 60 # grace before health checks start counting timeout = 120 # how long to wait for the app to come up ``

A fast /health endpoint is still the best default — these knobs are there for the genuinely slow boots.