refactor: remove unused wrapper functions and update documentation

- Remove unused localhost wrapper functions that were never called:
  - isPortOpen() - wrapper around isPortOpenOnIP with hardcoded 127.0.0.1
  - findAvailablePort() - wrapper around findAvailablePortOnIP with hardcoded 127.0.0.1
  - ensurePortAvailable() - wrapper around ensurePortAvailableOnIP with hardcoded 127.0.0.1
  - ensureAllPortsAvailable() - wrapper around ensureAllPortsAvailableOnIP with hardcoded 127.0.0.1

  Since this is new functionality with no backwards compatibility concerns,
  these wrapper functions were not needed. The comments claiming they were
  'kept for future use or backwards compatibility' are no longer valid.

- Update documentation to reference GrpcPortOffset constant instead of hardcoded 10000:
  - Update comment in ensureAllPortsAvailableOnIP to use GrpcPortOffset
  - Update admin.port.grpc flag help text to reference GrpcPortOffset

Note: getBindIp() is actually being used and should be retained (contrary to
the review comment suggesting it was unused - it's called in both runMini
and startMiniServices functions)

weed/command/mini.go

@@ -252,7 +252,7 @@ func initMiniWebDAVFlags() {
 // initMiniAdminFlags initializes Admin server flag options
 func initMiniAdminFlags() {
 	miniAdminOptions.port = cmdMini.Flag.Int("admin.port", 23646, "admin server http listen port")
-	miniAdminOptions.grpcPort = cmdMini.Flag.Int("admin.port.grpc", 0, "admin server grpc listen port (default: admin http port + 10000)")
+	miniAdminOptions.grpcPort = cmdMini.Flag.Int("admin.port.grpc", 0, "admin server grpc listen port (default: admin http port + GrpcPortOffset)")
 	miniAdminOptions.master = cmdMini.Flag.String("admin.master", "", "master server address (automatically set)")
 	miniAdminOptions.dataDir = cmdMini.Flag.String("admin.dataDir", "", "directory to store admin configuration and data files")
 	miniAdminOptions.adminUser = cmdMini.Flag.String("admin.user", "admin", "admin interface username")
@@ -336,13 +336,6 @@ func isFlagPassed(name string) bool {
 	return found
 }
 
-// isPortOpen checks if a port is available for binding on localhost
-// Note: This function is kept for potential future use or backwards compatibility.
-// Currently, all port checks use the IP-aware variants (isPortOpenOnIP, etc.)
-func isPortOpen(port int) bool {
-	return isPortOpenOnIP("127.0.0.1", port)
-}
-
 // isPortOpenOnIP checks if a port is available for binding on a specific IP address
 func isPortOpenOnIP(ip string, port int) bool {
 	listener, err := net.Listen("tcp", fmt.Sprintf("%s:%d", ip, port))
@@ -365,13 +358,6 @@ func isPortAvailable(port int) bool {
 	return true
 }
 
-// findAvailablePort finds the next available port starting from the given port
-// Note: This function is kept for potential future use or backwards compatibility.
-// Currently, all port allocation uses the IP-aware variant (findAvailablePortOnIP)
-func findAvailablePort(startPort int, maxAttempts int) int {
-	return findAvailablePortOnIP("127.0.0.1", startPort, maxAttempts)
-}
-
 // findAvailablePortOnIP finds the next available port on a specific IP starting from the given port
 // It returns the first available port found within maxAttempts, or 0 if none found
 func findAvailablePortOnIP(ip string, startPort int, maxAttempts int) int {
@@ -386,13 +372,6 @@ func findAvailablePortOnIP(ip string, startPort int, maxAttempts int) int {
 	return 0
 }
 
-// ensurePortAvailable ensures a port pointer points to an available port on localhost
-// Note: This function is kept for potential future use or backwards compatibility.
-// Currently, all port validation uses the IP-aware variant (ensurePortAvailableOnIP)
-func ensurePortAvailable(portPtr *int, serviceName string) {
-	ensurePortAvailableOnIP(portPtr, serviceName, "127.0.0.1")
-}
-
 // ensurePortAvailableOnIP ensures a port pointer points to an available port on a specific IP
 // If the port is not available, it finds the next available port and updates the pointer
 func ensurePortAvailableOnIP(portPtr *int, serviceName string, ip string) {
@@ -416,13 +395,6 @@ func ensurePortAvailableOnIP(portPtr *int, serviceName string, ip string) {
 	}
 }
 
-// ensureAllPortsAvailable ensures all mini service ports are available on localhost
-// Note: This function is kept for potential future use or backwards compatibility.
-// Currently, all port validation uses the IP-aware variant (ensureAllPortsAvailableOnIP)
-func ensureAllPortsAvailable() {
-	ensureAllPortsAvailableOnIP("127.0.0.1")
-}
-
 // ensureAllPortsAvailableOnIP ensures all mini service ports are available on a specific IP
 // This should be called before starting any services
 func ensureAllPortsAvailableOnIP(bindIp string) {
@@ -464,7 +436,7 @@ func ensureAllPortsAvailableOnIP(bindIp string) {
 }
 
 // initializeGrpcPortsOnIP initializes all gRPC ports based on their HTTP ports on a specific IP
-// If a gRPC port is 0, it will be set to httpPort + 10000
+// If a gRPC port is 0, it will be set to httpPort + GrpcPortOffset
 // This must be called after HTTP ports are finalized and before services start
 func initializeGrpcPortsOnIP(bindIp string) {
 	grpcConfigs := []struct {