security: remove mitmproxy certificates from CA bundle

- Remove mitmproxy trust source and certificate files from system
- Regenerate clean CA certificate bundle without mitmproxy
- Update project CA bundles with clean certificates
- Update .gitignore to prevent future commits of CA bundles

Fixes security concern with committed mitmproxy certificates that could
intercept HTTPS traffic and compromise SSL/TLS validation.

Author: kzndotsh

.gitignore

@@ -15,7 +15,9 @@ runtime/*/
 
 # SSL certificates and keys
 src/backend/unrealircd/conf/tls/*
-!src/backend/unrealircd/conf/tls/curl-ca-bundle.crt
+
+# CA certificate bundles (should be generated locally, not committed)
+docs/examples/unrealircd/tls/curl-ca-bundle.crt
 
 # Runtime data directories (created at runtime)
 data/