Extract strip_port_from_host into shared utils module and update normalize_host to properly strip brackets from IPv6 addresses like [::1]:443 -> ::1 instead of incorrectly using split(':').next().
Change ConfigReloadHandle.static_config from StaticConfig to ArcSwap<StaticConfig>
so that after each reload, the stored static config is updated with the new value.
This prevents repeated stale warnings about the same static config fields on
every reload.
Add routing table (HashMap<String, SiteConfig>) to DynamicConfig for
O(1) host lookup. Implement normalize_host (lowercase + strip port)
per RFC 7230 §2.7.3. Add proxy_handler that routes /health to 200,
missing Host to 400, unknown host to 404, and known host to 200.
Routing table updates atomically via ArcSwap.
Add ConfigReloadHandle with Arc<ArcSwap<DynamicConfig>> for lock-free reads
on the request hot path and tokio::sync::Mutex-serialized reload. Add static
config change detection via diff_static_config(). Add DynamicConfig validation
(rate_limit, body_limit, site checks). Add PartialEq derives to config types.
Include unit tests for ArcSwap swap visibility, invalid config rejection, and
concurrent reload serialization.
