feat(api): HTTP readiness knob on MinecraftServer and login-gate fallback default

StartupSpec.HealthHTTPPort/Path switch pod readiness from plain-TCP to an HTTP GET for RCON-less loaders (LOOHP/Limbo) that report 'started' only after the first tick. User servers now default FallbackServer to the login gate, never the lobby, so a stopped/starting backend keeps authentication in front of a fresh connection.

deploy/crd/felis.lolicon.best_minecraftservers.yaml

@@ -243,6 +243,18 @@ spec:
                 description: Startup bounds how long Starting may last before Failed
                   (spec §5).
                 properties:
+                  healthHTTPPath:
+                    description: HealthHTTPPath is the path for the HTTP readiness
+                      probe (default "/healthz" when HealthHTTPPort is set).
+                    type: string
+                  healthHTTPPort:
+                    description: HealthHTTPPort, when > 0, switches the pod readiness
+                      probe from the default plain-TCP check on the game port to an
+                      HTTP GET on this container port. It exists for RCON-less loaders
+                      (notably LOOHP/Limbo) where the felis-limbo plugin reports true
+                      readiness only after the first server tick.
+                    format: int32
+                    type: integer
                   readinessTimeoutSeconds:
                     description: ReadinessTimeoutSeconds is the budget for the first
                       successful RCON probe.