security: fix 17 vulnerabilities from comprehensive pentest

Fixes identified from full security audit covering auth, crypto,
injection, infrastructure, and configuration security.

Critical:
- C1: Fail-closed on unrecognized NODE_ENV (prevent DEV_SECRET in staging)
- C3: Validate API token expires_at (reject invalid dates that bypass expiry)

High:
- H1: Refresh JWT role from DB on each session (reflect demotions immediately)
- H2: Docker socket proxy for l4-port-manager (restrict API surface)
- H5: Block dangerous WAF custom directives (SecRuleEngine, SecAuditEngine)
- H7: Require explicit NEXTAUTH_TRUST_HOST instead of always trusting Host
- H8: Semantic validation of sync payload (block metadata SSRF, size limits)

Medium:
- M3: Rate limit password change current-password verification
- M5: Parameterized SQL in log/waf parsers (replace template literals)
- M6: Nonce-based CSP replacing unsafe-inline for script-src
- M9: Strip Caddy placeholders from rewrite path_prefix
- M10: Sanitize authentik outpostDomain (path traversal, placeholders)
- M14: Deny access on missing JWT role instead of defaulting to "user"

Low:
- L1: Require Origin header on mutating session-authenticated requests
- L4: Enforce password complexity on user password changes
- L5: Time-limited legacy SHA-256 key fallback (grace period until 2026-06-01)
- L6: Escape LIKE metacharacters in audit log search
- L7: Runtime-validate WAF excluded_rule_ids as positive integers

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/lib/api-auth.ts

@@ -46,9 +46,15 @@ export async function authenticateApiRequest(
     throw new ApiAuthError("Unauthorized", 401);
   }
 
+  // M14: Deny access when role is missing rather than defaulting to "user"
+  const role = session.user.role;
+  if (!role) {
+    throw new ApiAuthError("Session missing role claim", 401);
+  }
+
   return {
     userId: Number(session.user.id),
-    role: session.user.role ?? "user",
+    role,
     authMethod: "session",
   };
 }