Require consent before sending the token over plain http to a non-loopback
host, strip control characters from server-supplied text, restrict env values
and tokens to printable ASCII, validate the URLs like other env values and
fsync the directory after the atomic replace.
Verifies the Gitea instance, token and scopes, registers or reuses the aegis-gitea-mcp OAuth app, generates missing secrets and writes a 0600 env file from the template. Prints client configs and deployment snippets without any secret value.