feat: add filename linter and AI coding guidelines (#1477)

Add a configurable filename linter to enforce naming conventions and an AGENTS.md to guide
AI coding agents in following project conventions.

The guidelines steer code generation; the linter independently verifies filename compliance.
Together, they improve consistency and reduce unnecessary files and review effort.

Conflicting file names were renamed.

Signed-off-by: Bobby Noelte <b0661n0e17e@gmail.com>

src/akkudoktoreos/server/eos.py

@@ -73,7 +73,7 @@ from akkudoktoreos.prediction.load import LoadCommonSettings
 from akkudoktoreos.prediction.loadakkudoktor import LoadAkkudoktorCommonSettings
 from akkudoktoreos.prediction.pvforecast import PVForecastCommonSettings
 from akkudoktoreos.prediction.pvforecastpvlib import _cec_inverters, _cec_modules
-from akkudoktoreos.server.container_healthcheck import publish_port
+from akkudoktoreos.server.containerhealthcheck import publish_port
 from akkudoktoreos.server.rest.error import (
     EOSProblem,
     create_error_page,