feat: expose Buildbot via nginx proxy on LAN

Add greg.proxies entries on jeremiah for buildbot.home and
buildbot.thehellings.lan, both proxying to http://localhost:8010/.
Nginx handles auth passthrough - Buildbot's own Gitea OAuth applies.

Add DNS aliases in genesis hosts file:
- buildbot.thehellings.lan → 10.42.1.8 (LAN)
- buildbot.home → 100.102.186.39 (Tailscale)

hosts/unstable/genesis/net/hosts

@@ -12,7 +12,7 @@
 10.42.1.5 genesis genesis.thehellings.lan dns dns.thehellings.lan smart smart.thehellings.lan speedtest.thehellings.lan nixcache.thehellings.lan gitcache.thehellings.lan
 10.42.1.6 isaiah isaiah.thehellings.lan minio-01.thehellings.lan
 10.42.1.7 hosea hosea.thehellings.lan jellyfin jellyfin.thehellings.lan grafana grafana.thehellings.lan
-10.42.1.8 jeremiah jeremiah.thehellings.lan minio-02.thehellings.lan
+10.42.1.8 jeremiah jeremiah.thehellings.lan minio-02.thehellings.lan buildbot.thehellings.lan
 10.42.1.9 ivr ivr.thehellings.lan
 # 10 - monitor
 # 11 - old jude
@@ -40,7 +40,7 @@
 100.117.28.111 gitlab.home gitlab.shire-zebra.ts.net gitlab.thehellings.lan registry.thehellings.lan git.thehellings.lan
 100.68.203.1 hosea.home hosea.shire-zebra.ts.net grafana.home
 100.84.183.79 isaiah.home isaiah.shire-zebra.ts.net pgadmin.kubernetes longhorn.kubernetes
-100.102.186.39 jeremiah.home jeremiah.shire-zebra.ts.net matrix.kubernetes immich.kubernetes postgres.kubernetes
+100.102.186.39 jeremiah.home jeremiah.shire-zebra.ts.net matrix.kubernetes immich.kubernetes postgres.kubernetes buildbot.home
 100.90.74.19 zeke.home zeke.shire-zebra.ts.net
 100.109.86.8 linode.home linode.shire-zebra.ts.net
 100.65.5.38 matrix.home matrix.shire-zebra.ts.net

hosts/unstable/jeremiah/default.nix

@@ -85,6 +85,13 @@ in
       vip = ip;
       priority = 254;
     };
+    proxies = {
+      # Expose Buildbot over HTTP on the LAN so Klaatu (and other internal
+      # tools) can reach it without Tailscale.  Buildbot's own Gitea OAuth
+      # handles authentication.
+      "buildbot.home".target = "http://localhost:8010/";
+      "buildbot.thehellings.lan".target = "http://localhost:8010/";
+    };
     tailscale = {
       enable = true;
       tags = [ "home" ];