refactor(config): generate paas profile from default overlay

docs/deployment/PAAS.md

@@ -7,7 +7,18 @@ Key requirements:
 - Bind on all interfaces: set `server.localhost: false`.
 - Use the platform port: Flynn supports `PORT` env override (it overrides `server.port`).
 
-This repo includes a PaaS-friendly config template at `config/paas.yaml`.
+This repo includes a PaaS-friendly config profile at `config/profiles/paas.overlay.yaml`.
+
+`config/paas.yaml` is generated from:
+- `config/default.yaml` (canonical base)
+- `config/profiles/paas.overlay.yaml` (PaaS overrides only)
+
+Regenerate/check with:
+
+```bash
+pnpm config:profiles:generate
+pnpm config:profiles:check
+```
 
 ## Fly.io
 
@@ -53,4 +64,3 @@ Checklist:
 - Ensure your config binds externally (`server.localhost: false`) or use the baked-in `config/paas.yaml`.
 
 Optional blueprint: `deploy/render/render.yaml`
-