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_capability_test.go

@@ -0,0 +1,52 @@
+package controller
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/nezhahq/nezha/model"
+)
+
+// 旧 agent 不识别 TaskTypeExec/TaskTypeFs* 等新 task type，会走 default
+// 分支不回 TaskResult；dashboard 必须在调 CallAgent 之前依据 Host.Version
+// 快速失败，否则用户要等到 30s/24h timeout 才知道 agent 不支持。
+// MinServerTransferAgentVersion 已为同类问题在 transfer 路径上确立了
+// release-time 必填的版本下限——这里把 MCP 也纳入同一不变量。
+func TestMCPMinAgentVersionIsPinnedToRelease(t *testing.T) {
+	require.NotEmpty(t, MCPMinAgentVersion,
+		"MCPMinAgentVersion must be set to the lowest agent build that ships MCP handlers; an empty string disables the gate and lets old agents hang dashboard requests until timeout")
+}
+
+func TestRequireAgentSupportsMCPRejectsBelowMinVersion(t *testing.T) {
+	old := &model.Server{Host: &model.Host{Version: "v0.0.1"}}
+	err := requireAgentSupportsMCP(old)
+	require.Error(t, err, "agents older than MCPMinAgentVersion must be rejected before CallAgent")
+	require.True(t, errors.Is(err, errMCPUnsupported) || err.Error() == errMCPUnsupported.Error(),
+		"expected the errMCPUnsupported sentinel, got %v", err)
+}
+
+func TestRequireAgentSupportsMCPAcceptsCurrentVersion(t *testing.T) {
+	current := &model.Server{Host: &model.Host{Version: MCPMinAgentVersion}}
+	require.NoError(t, requireAgentSupportsMCP(current),
+		"server reporting exactly MCPMinAgentVersion must be accepted")
+}
+
+// 钉住「最近一个不带 MCP handler 的已发布 agent tag (v2.0.4) 必须被拒绝」。
+// v2.0.4 的 model/task.go 还没有 TaskTypeExec/TaskTypeFs* 常量，cmd/agent/
+// mcp_handlers.go 也不存在；如果版本门槛把它放行，dashboard 调 MCP tool
+// 后 agent 会走 default 分支不回 TaskResult，CallAgent 必须等 30s 超时。
+func TestRequireAgentSupportsMCPRejectsLastReleaseWithoutMCP(t *testing.T) {
+	noMCP := &model.Server{Host: &model.Host{Version: "v2.0.4"}}
+	err := requireAgentSupportsMCP(noMCP)
+	require.Error(t, err,
+		"v2.0.4 is the latest released agent tag that ships *without* MCP handlers; bumping MCPMinAgentVersion below the first MCP release re-introduces the silent-timeout bug")
+	require.True(t, errors.Is(err, errMCPUnsupported) || err.Error() == errMCPUnsupported.Error(),
+		"expected the errMCPUnsupported sentinel, got %v", err)
+}
+
+func TestRequireAgentSupportsMCPDefersWhenAgentNeverReported(t *testing.T) {
+	require.NoError(t, requireAgentSupportsMCP(&model.Server{Host: nil}),
+		"Host==nil means agent never reported its build; defer the version decision to the CallAgent timeout layer")
+}