Add per-service customization, stealth hardening, and BYOS support

- HTTP: configurable server_header, response_code, fake_app presets
  (apache/nginx/wordpress/phpmyadmin/iis), extra_headers, custom_body,
  static files directory mount
- SSH/Cowrie: configurable kernel_version, hardware_platform, ssh_banner,
  and users/passwords via COWRIE_USERDB_ENTRIES; switched to build mode
  so cowrie.cfg.j2 persona fields and userdb.txt generation work
- SMTP: configurable banner and MTA hostname
- MySQL: configurable version string in protocol greeting
- Redis: configurable redis_version and os string in INFO response
- BYOS: [custom-*] INI sections define bring-your-own Docker services
- Stealth: rename all *_honeypot.py → server.py; replace HONEYPOT_NAME
  env var with NODE_NAME across all 22+ service templates and plugins;
  strip "honeypot" from all in-container file content
- Config: DeckyConfig.service_config dict; INI [decky-N.svc] subsections;
  composer passes service_cfg to compose_fragment
- 350 tests passing (100%)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

decnet/services/base.py

@@ -15,7 +15,12 @@ class BaseService(ABC):
     default_image: str  # Docker image tag, or "build" if a Dockerfile is needed
 
     @abstractmethod
-    def compose_fragment(self, decky_name: str, log_target: str | None = None) -> dict:
+    def compose_fragment(
+        self,
+        decky_name: str,
+        log_target: str | None = None,
+        service_cfg: dict | None = None,
+    ) -> dict:
         """
         Return the docker-compose service dict for this service on a given decky.
 
@@ -26,6 +31,7 @@ class BaseService(ABC):
         Args:
             decky_name: unique identifier for the decky (e.g. "decky-01")
             log_target: "ip:port" string if log forwarding is enabled, else None
+            service_cfg: optional per-service persona config from INI subsection
         """
 
     def dockerfile_context(self) -> Path | None: