feat: YAML config for all server tunables
- server.Config + DefaultConfig + LoadConfig/ParseConfig (yaml.v3)
- all operator knobs now configurable: listen addr, audience, data dir,
log level, per-IP rate limits, per-subject quota, challenge/session TTLs,
max body bytes
- server.New takes Config; flags (-addr/-audience/-data/-config) override the
file; missing config.yaml falls back to defaults
- config.yaml.example committed as template; config.yaml git-ignored
- tests for config defaults/parsing/partial override
Niko Marmeladkov
d957108ac1
