Install script, static assets, UI and release workflow updates

- install.sh: default dirs, --update/--service/--uninstall/--purge, in-dir dnsmasq-webui symlink, ContentRootPath note
- UseStaticFiles instead of MapStaticAssets (fix 0-byte assets)
- Program: ContentRootPath when not Development for symlink/CWD
- App.razor: direct asset paths
- Dnsmasq page: remove redundant status pre, margin above Reload button
- Sidebar: logo 64px via app.css, hamburger vertically centered, toggler inside top-row
- ApplicationTitle documented in README
- publish/release: RIDs, Docker build for glibc

testdata/dnsmasq-test.conf

@@ -1,4 +1,4 @@
-# Config for the dnsmasq test container only (docker-compose.test.yml).
+# Config for the dnsmasq test container only (docker-compose.test.yml).
 # DNS + DHCP: forwards DNS to Cloudflare/Google with caching; hands out DHCP on testnet.
 # Uses same testdata layout so app and dnsmasq share hosts, dhcp.conf, leases.
 # Richer config so UI shows multi-value lists (server, addn-hosts, address, dhcp-range) and readonly sources.
@@ -31,4 +31,6 @@ addn-hosts=/data/hosts.extra
 
 # Log to file so the harness can show real logs (LogsCommand tails this)
 log-facility=/data/dnsmasq.log
-log-queries
+log-queries
+
+conf-file=zz-dnsmasq-webui.conf

testdata/dnsmasq.conf

@@ -1,4 +1,6 @@
-# Sample main dnsmasq config (not managed by this app).
+# Sample main dnsmasq config (not managed by this app).
 # In production this would typically be /etc/dnsmasq.conf.
 # It includes all .conf files from dnsmasq.d/ (e.g. dhcp.conf managed by this app).
 conf-dir=/etc/dnsmasq.d/
+
+conf-file=zz-dnsmasq-webui.conf