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_body_limit_test.go

@@ -0,0 +1,72 @@
+package controller
+
+import (
+	"bytes"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"github.com/gin-gonic/gin"
+
+	"github.com/nezhahq/nezha/model"
+	"github.com/nezhahq/nezha/service/singleton"
+)
+
+// H7 regression: the MCP endpoint must cap incoming JSON-RPC body size
+// BEFORE decoding. Without this, a valid PAT can post a multi-GB body and
+// the dashboard exhausts memory in ShouldBindJSON. We assert the body
+// reader is wrapped in http.MaxBytesReader; the exact error path the
+// decoder takes is irrelevant as long as the cap is enforced.
+func TestMCPEndpoint_BodyIsCappedByMaxBytesReader(t *testing.T) {
+	prevConf := singleton.Conf
+	cfg := &model.Config{}
+	cfg.SetMCPEnabled(true)
+	singleton.Conf = &singleton.ConfigClass{Config: cfg}
+	t.Cleanup(func() { singleton.Conf = prevConf })
+
+	tok := &model.APIToken{ID: 1, ScopesCSV: "nezha:server:read"}
+	// 16 MiB of valid-JSON whitespace prefix forces the decoder to actually
+	// stream past the limit, exercising MaxBytesReader.
+	body := `{"jsonrpc":"2.0","id":1,"method":"initialize","params":"` +
+		strings.Repeat("x", mcpJSONRPCMaxBodyBytes+1024) + `"}`
+	req := httptest.NewRequest(http.MethodPost, "/mcp", bytes.NewBufferString(body))
+	req.Header.Set("Content-Type", "application/json")
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	c.Request = req
+	c.Set(apiTokenCtxKey, tok)
+	c.Set(model.CtxKeyAPIToken, tok)
+
+	mcpEndpoint(c)
+
+	if !strings.Contains(w.Body.String(), "request body") &&
+		w.Code != http.StatusRequestEntityTooLarge {
+		t.Fatalf("oversized body must be rejected with a body-size error, got code=%d body=%s",
+			w.Code, w.Body.String())
+	}
+}
+
+func TestMCPEndpoint_AcceptsSmallBody(t *testing.T) {
+	prevConf := singleton.Conf
+	cfg := &model.Config{}
+	cfg.SetMCPEnabled(true)
+	singleton.Conf = &singleton.ConfigClass{Config: cfg}
+	t.Cleanup(func() { singleton.Conf = prevConf })
+
+	tok := &model.APIToken{ID: 1, ScopesCSV: "nezha:server:read"}
+	body := `{"jsonrpc":"2.0","id":1,"method":"initialize"}`
+	req := httptest.NewRequest(http.MethodPost, "/mcp", bytes.NewBufferString(body))
+	req.Header.Set("Content-Type", "application/json")
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	c.Request = req
+	c.Set(apiTokenCtxKey, tok)
+	c.Set(model.CtxKeyAPIToken, tok)
+
+	mcpEndpoint(c)
+
+	if w.Code != http.StatusOK {
+		t.Fatalf("small valid body must succeed, got code=%d body=%s", w.Code, w.Body.String())
+	}
+}