feat(auth): add PAT auth, scoped REST/MCP access, CSRF, and tenant isolation

Introduce Personal Access Tokens (nzp_*) as a stateless auth path alongside
JWT, gated per-endpoint by a scope middleware (nezha:{resource}:{verb}) with
fail-closed empty-scope defaults and a server-id whitelist. Self-management
endpoints (profile, api-tokens, oauth2 bind, refresh-token) explicitly reject
PATs to block privilege-escalation chains. A revoke registry tears down active
long-lived connections (terminal, fm, ws, transfer, mcp) the moment a PAT is
deleted, with a tombstone closing the revoke->register race.

Add an MCP endpoint that proxies tool calls (exec, fs read/write/delete,
transfer) to agents over gRPC, guarded by origin/DNS-rebinding checks, a
per-token rate limiter, audit logging, and a kill switch. Serialize all
sends through the IOStream wrapper to honour grpc-go's concurrency contract.

Add CSRF double-submit protection on unsafe cookie-authenticated methods,
exempting authenticated PAT requests by context identity (not a forgeable
Authorization header). Apply visibility/whitelist filtering consistently
across list, get-by-id, and mutate paths to enforce tenant isolation.

Migrate legacy mcp:* scopes: rewrite read/exec to nezha:* equivalents and
drop dangerous write/delete/wildcard grants.

Co-authored-by: cloudcode <cloudcode@users.noreply.github.com>

cmd/dashboard/controller/mcp_transfer_spool.go

@@ -0,0 +1,44 @@
+package controller
+
+import (
+	"io"
+	"os"
+	"runtime"
+)
+
+type transferSpool struct {
+	f *os.File
+}
+
+func newTransferSpool() (*transferSpool, error) {
+	f, err := os.CreateTemp("", "nz-mcp-xfer-*")
+	if err != nil {
+		return nil, err
+	}
+	// 提前 unlink，文件句柄关掉就回收磁盘；Windows 不支持就留到 Close 兜底。
+	if runtime.GOOS != "windows" {
+		_ = os.Remove(f.Name())
+	}
+	return &transferSpool{f: f}, nil
+}
+
+func (s *transferSpool) Write(p []byte) (int, error) { return s.f.Write(p) }
+
+func (s *transferSpool) Read(p []byte) (int, error) { return s.f.Read(p) }
+
+func (s *transferSpool) Rewind() error {
+	_, err := s.f.Seek(0, io.SeekStart)
+	return err
+}
+
+func (s *transferSpool) Close() {
+	if s.f == nil {
+		return
+	}
+	name := s.f.Name()
+	_ = s.f.Close()
+	if runtime.GOOS == "windows" {
+		_ = os.Remove(name)
+	}
+	s.f = nil
+}