Harden deployment and fix PEN-01

- Fix Bearer token extraction to validate prefix (PEN-01)
- Add TestExtractBearerFromRequest covering PEN-01 edge cases
- Fix flaky TestRenewToken timing (2s → 4s lifetime)
- Move default config/install paths to /srv/mcias
- Add RUNBOOK.md for operational procedures
- Update AUDIT.md with penetration test round 4

Security: extractBearerFromRequest now uses case-insensitive prefix
validation instead of fixed-offset slicing, rejecting non-Bearer
Authorization schemes that were previously accepted.

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

dist/mcias.service

@@ -11,11 +11,11 @@ User=mcias
 Group=mcias
 
 # Configuration and secrets.
-# /etc/mcias/env must contain MCIAS_MASTER_PASSPHRASE=<passphrase>
+# /srv/mcias/env must contain MCIAS_MASTER_PASSPHRASE=<passphrase>
 # See dist/mcias.env.example for the template.
-EnvironmentFile=/etc/mcias/env
+EnvironmentFile=/srv/mcias/env
 
-ExecStart=/usr/local/bin/mciassrv -config /etc/mcias/mcias.conf
+ExecStart=/usr/local/bin/mciassrv -config /srv/mcias/mcias.toml
 Restart=on-failure
 RestartSec=5
 
@@ -30,11 +30,11 @@ LimitNOFILE=65536
 CapabilityBoundingSet=
 
 # Filesystem restrictions.
-# mciassrv reads /etc/mcias (config, TLS cert/key) and writes /var/lib/mcias (DB).
+# mciassrv reads and writes /srv/mcias (config, TLS cert/key, database).
 ProtectSystem=strict
 ProtectHome=true
 PrivateTmp=true
-ReadWritePaths=/var/lib/mcias
+ReadWritePaths=/srv/mcias
 
 # Additional hardening.
 NoNewPrivileges=true