Remove the RDMA sidecar prototype and its mount client (#11119)

* rdma: drop the sidecar prototype

The Rust engine under it never touched a wire: rdma.rs fabricates pattern
bytes and the crate's default feature is mock-ucx, with real-ucx unimplemented
since the directory landed. Nothing builds it, no CI runs it, and its only
consumer is weed mount's RDMA client, removed next. Two 22MB binaries were
committed along with it.

Claude-Session: https://claude.ai/code/session_01X3zhqLYwQwEQCrRbuzQKvy

* mount: remove the RDMA client that spoke to the deleted sidecar

Its only server was the sidecar's HTTP API, and the path could never have
worked in production anyway: it served a single chunk per call, ignored the
buffer's chunk boundaries, and had no test. Removing it also removes the
per-handle cumulative-offset cache, which nothing else used.

The -rdma.* mount flags go with it. They defaulted to off and pointed at an
address no released build ever listened on.

Claude-Session: https://claude.ai/code/session_01X3zhqLYwQwEQCrRbuzQKvy

weed/command/mount.go

@@ -48,14 +48,6 @@ type MountOptions struct {
 	// Periodic metadata flush to protect against orphan chunk cleanup
 	metadataFlushSeconds *int
 
-	// RDMA acceleration options
-	rdmaEnabled       *bool
-	rdmaSidecarAddr   *string
-	rdmaFallback      *bool
-	rdmaReadOnly      *bool
-	rdmaMaxConcurrent *int
-	rdmaTimeoutMs     *int
-
 	// Peer chunk sharing options (design-weed-mount-peer-chunk-sharing.md).
 	peerEnabled    *bool
 	peerListen     *string
@@ -139,14 +131,6 @@ func init() {
 	// Periodic metadata flush to protect against orphan chunk cleanup
 	mountOptions.metadataFlushSeconds = cmdMount.Flag.Int("metadataFlushSeconds", 120, "periodically flush file metadata to filer in seconds (0 to disable). This protects chunks from being purged by volume.fsck for long-running writes")
 
-	// RDMA acceleration flags
-	mountOptions.rdmaEnabled = cmdMount.Flag.Bool("rdma.enabled", false, "enable RDMA acceleration for reads")
-	mountOptions.rdmaSidecarAddr = cmdMount.Flag.String("rdma.sidecar", "", "RDMA sidecar address (e.g., localhost:8081)")
-	mountOptions.rdmaFallback = cmdMount.Flag.Bool("rdma.fallback", true, "fallback to HTTP when RDMA fails")
-	mountOptions.rdmaReadOnly = cmdMount.Flag.Bool("rdma.readOnly", false, "use RDMA for reads only (writes use HTTP)")
-	mountOptions.rdmaMaxConcurrent = cmdMount.Flag.Int("rdma.maxConcurrent", 64, "max concurrent RDMA operations")
-	mountOptions.rdmaTimeoutMs = cmdMount.Flag.Int("rdma.timeoutMs", 5000, "RDMA operation timeout in milliseconds")
-
 	// Peer chunk sharing flags.
 	mountOptions.peerEnabled = cmdMount.Flag.Bool("peer.enable", false, "opt in to peer chunk sharing — mount serves its chunk cache to other mounts and fetches from peers instead of volume servers when available")
 	mountOptions.peerListen = cmdMount.Flag.String("peer.listen", ":18080", "bind address for peer gRPC (directory RPCs + FetchChunk streaming)")
@@ -205,18 +189,5 @@ var cmdMount = &Command{
   -dir=\\seaweedfs\Images labels the disk "Images" while still mounting
   everything, and only a bare drive letter falls back to the filer address.
 
-  RDMA Acceleration:
-  For ultra-fast reads, enable RDMA acceleration with an RDMA sidecar:
-    weed mount -filer=localhost:8888 -dir=/mnt/seaweedfs \
-      -rdma.enabled=true -rdma.sidecar=localhost:8081
-
-  RDMA Options:
-    -rdma.enabled=false          Enable RDMA acceleration for reads
-    -rdma.sidecar=""             RDMA sidecar address (required if enabled)
-    -rdma.fallback=true          Fallback to HTTP when RDMA fails
-    -rdma.readOnly=false         Use RDMA for reads only (writes use HTTP)
-    -rdma.maxConcurrent=64       Max concurrent RDMA operations
-    -rdma.timeoutMs=5000         RDMA operation timeout in milliseconds
-
   `,
 }

weed/command/mount_common.go

@@ -221,18 +221,11 @@ func buildSeaweedFileSystem(option *MountOptions, p fileSystemParams) *mount.WFS
 		DisableXAttr:                *option.disableXAttr,
 		IsMacOs:                     runtime.GOOS == "darwin",
 		MetadataFlushSeconds:        *option.metadataFlushSeconds,
-		// RDMA acceleration options
-		RdmaEnabled:           *option.rdmaEnabled,
-		RdmaSidecarAddr:       *option.rdmaSidecarAddr,
-		RdmaFallback:          *option.rdmaFallback,
-		RdmaReadOnly:          *option.rdmaReadOnly,
-		RdmaMaxConcurrent:     *option.rdmaMaxConcurrent,
-		RdmaTimeoutMs:         *option.rdmaTimeoutMs,
-		DirIdleEvictSec:       *option.dirIdleEvictSec,
-		EnableDistributedLock: option.distributedLock != nil && *option.distributedLock,
-		WritebackCache:        option.writebackCache != nil && *option.writebackCache,
-		EagerFilerCreate:      p.eagerFilerCreate,
-		PosixDirNlink:         option.posixDirNlink != nil && *option.posixDirNlink,
+		DirIdleEvictSec:             *option.dirIdleEvictSec,
+		EnableDistributedLock:       option.distributedLock != nil && *option.distributedLock,
+		WritebackCache:              option.writebackCache != nil && *option.writebackCache,
+		EagerFilerCreate:            p.eagerFilerCreate,
+		PosixDirNlink:               option.posixDirNlink != nil && *option.posixDirNlink,
 		// Peer chunk sharing
 		PeerEnabled:    option.peerEnabled != nil && *option.peerEnabled,
 		PeerListen:     peerStringOrEmpty(option.peerListen),