feat: add ACME account management with validation pipeline

- Register, view, and deactivate ACME accounts via API and UI
- 16-check validation framework for certificate issuance readiness
- DNS resolution, port, nginx, and firewall pre-flight checks
- External IP detection with NAT support and fallback providers
- Account card and settings modal in certificates page
- Guard certificate issuance behind account registration
- Update modal CSS to overlay-based approach
- 1000+ lines of tests for validation and account handlers

lib/acme.py

@@ -147,14 +147,15 @@ def _read_acme_email() -> str:
     """Read ACME email from account.conf, falling back to declarative config."""
     try:
         acme_home = Path(os.environ.get("ACME_HOME", str(_ACME_HOME)))
-        account_conf = acme_home / "account.conf"
-        if account_conf.is_file():
-            text = account_conf.read_text()
-            match = re.search(r"^ACME_LEEMAIL=(.+)$", text, re.MULTILINE)
-            if match:
-                return match.group(1).strip().strip("'\"")
+        for conf_name in (".account.conf", "account.conf"):
+            account_conf = acme_home / conf_name
+            if account_conf.is_file():
+                text = account_conf.read_text()
+                match = re.search(r"^ACME_LEEMAIL=(.+)$", text, re.MULTILINE)
+                if match:
+                    return match.group(1).strip().strip("'\"")
     except OSError as exc:
-        logger.warning("Could not read account.conf: %s", exc)
+        logger.warning("Could not read account config: %s", exc)
     # Fallback: read from declarative ACME config
     try:
         from lib.common import load_json