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-dev.conf.example

@@ -15,7 +15,7 @@
 #   export MCIAS_MASTER_PASSPHRASE=devpassphrase
 #
 # Start the server:
-#   mciassrv -config /path/to/mcias-dev.conf
+#   mciassrv -config /path/to/mcias-dev.toml
 
 [server]
 listen_addr = "127.0.0.1:8443"