Serve HTTPS by default with a local CA

The installer generates a CA and a 397-day certificate into
$COBBLE_HOME/certs (in the app image, with the host's addresses), mounts
the certificate, key and CA into the container and serves TLS from Bun on
the published port. --no-https opts out; --https-cert/--https-key use a
real certificate, --https-host adds names and --https-regen replaces the
CA. The installer and the image health check use curl -k when TLS is on.

The CA is served at /ca.crt and as an iOS/macOS profile at
/ca.mobileconfig for one-tap install. Development picks up certs/
automatically, `bun run dev:phone` generates and starts, and a plain-HTTP
listener on PORT + 1 redirects to HTTPS. Port sharing is off, so a stale
dev server fails instead of silently answering on the same port.

.gitignore

@@ -39,6 +39,9 @@ report.[0-9]_.[0-9]_.[0-9]_.[0-9]_.json
 /test
 /.bunext
 
+# locally generated HTTPS certificates (bun run gen:certs)
+/certs
+
 # bun-sqlite local database + artifacts
 /db/cobble
 /db/.backups