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/http.py

@@ -1,3 +1,4 @@
+import json
 from pathlib import Path
 from decnet.services.base import BaseService
 
@@ -9,17 +10,43 @@ class HTTPService(BaseService):
     ports = [80, 443]
     default_image = "build"
 
-    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:
+        cfg = service_cfg or {}
         fragment: dict = {
             "build": {"context": str(TEMPLATES_DIR)},
             "container_name": f"{decky_name}-http",
             "restart": "unless-stopped",
             "environment": {
-                "HONEYPOT_NAME": decky_name,
+                "NODE_NAME": decky_name,
             },
         }
         if log_target:
             fragment["environment"]["LOG_TARGET"] = log_target
+
+        # Optional persona overrides — only injected when explicitly set
+        if "server_header" in cfg:
+            fragment["environment"]["SERVER_HEADER"] = cfg["server_header"]
+        if "response_code" in cfg:
+            fragment["environment"]["RESPONSE_CODE"] = str(cfg["response_code"])
+        if "fake_app" in cfg:
+            fragment["environment"]["FAKE_APP"] = cfg["fake_app"]
+        if "extra_headers" in cfg:
+            val = cfg["extra_headers"]
+            fragment["environment"]["EXTRA_HEADERS"] = (
+                json.dumps(val) if isinstance(val, dict) else val
+            )
+        if "custom_body" in cfg:
+            fragment["environment"]["CUSTOM_BODY"] = cfg["custom_body"]
+        if "files" in cfg:
+            files_path = str(Path(cfg["files"]).resolve())
+            fragment["environment"]["FILES_DIR"] = "/opt/html_files"
+            fragment.setdefault("volumes", []).append(f"{files_path}:/opt/html_files:ro")
+
         return fragment
 
     def dockerfile_context(self) -> Path | None: