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_audit.go

@@ -0,0 +1,48 @@
+package controller
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"log"
+	"time"
+
+	"github.com/nezhahq/nezha/model"
+	"github.com/nezhahq/nezha/service/singleton"
+)
+
+// mcpAuditWrite 异步写一条 MCP 审计日志。失败仅 log，不阻塞业务。
+//
+// argsBytes：tool 的 raw JSON 参数（dispatcher 已经反序列化过）。
+// 只记录 sha256 全文哈希，不保留任何明文片段：server.exec 的 env/stdin、
+// fs.write 的 content 等字段会包含 token、密码、密钥、文件内容等敏感数据，
+// 任何长度的 peek 都可能让审计表本身成为 secret 仓库；以哈希做关联即可。
+//
+// 测试可以把 mcpAuditSync 置为 true 让写入同步，避免 goroutine 与测试 teardown
+// 形成竞态（不同测试 swap 全局 singleton.DB 时尤其明显）。
+func mcpAuditWrite(entry model.MCPAuditLog, argsBytes []byte) {
+	if len(argsBytes) > 0 {
+		sum := sha256.Sum256(argsBytes)
+		entry.ArgsHash = hex.EncodeToString(sum[:])
+	}
+	entry.ArgsPeek = ""
+	if entry.CreatedAt.IsZero() {
+		entry.CreatedAt = time.Now()
+	}
+	db := singleton.DB
+	write := func(e model.MCPAuditLog) {
+		if db == nil {
+			return
+		}
+		if err := db.Create(&e).Error; err != nil {
+			log.Printf("NEZHA>> mcp audit write failed: %v", err)
+		}
+	}
+	if mcpAuditSync {
+		write(entry)
+		return
+	}
+	go write(entry)
+}
+
+// mcpAuditSync 仅供测试切换为同步写入，生产保持 false。
+var mcpAuditSync = false