When resolveInboundMTLSProfileForRoute fails for the global profile, emit a
zerolog error and continue without applying that pool. Apply inbound mTLS from
the global profile only when err is nil and pool is non-nil.
Add yaml struct tags to InboundMTLSProfile alongside json for YAML config
loading.
Clarify no-op stub methods in inbound_mtls_validation_test with comments.
Add root-level inbound_mtls_profiles combining optional system CAs with PEM
CA files, and entrypoint.inbound_mtls_profile to require client certificates
on every HTTPS connection. Route-level inbound_mtls_profile is allowed only
without a global profile; per-handshake TLS picks ClientCAs from SNI, and
requests fail with 421 when Host and SNI would select different mTLS routes.
Compile pools at init (SetInboundMTLSProfiles from state.initEntrypoint) and
reject unknown profile refs or mixed global-plus-route configuration.
Extend config.example.yml and package READMEs; add entrypoint and config
tests for TLS mutation, handshakes, and validation.
