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_gc_test.go

@@ -0,0 +1,53 @@
+package controller
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+)
+
+// transferEntries 是 mint→consume 的内存表。
+// mintTransferToken 把 token Store 进去，consumeTransferToken 命中后才删，
+// PurgeTransferEntries 是 kill switch 的全量清理。这条路径目前缺一个
+// 按 ExpiresAt 的过期回收：从未被 consume 的 token 会一直留到下一次
+// kill switch 才被清掉。
+//
+// 这条测试钉死「过期项必须被 gcExpiredTransferEntries() 清掉，
+// 且未过期项必须保留」。
+func TestGCExpiredTransferEntries_RemovesOnlyExpired(t *testing.T) {
+	// 隔离全局状态，避免被其它测试遗留的 entry 干扰。
+	PurgeTransferEntries()
+	t.Cleanup(func() { PurgeTransferEntries() })
+
+	now := time.Now()
+	expiredTok, err := mintTransferToken(transferEntry{
+		UserID:    1,
+		TokenID:   1,
+		ServerID:  1,
+		Path:      "/srv/expired",
+		Direction: transferDirDownload,
+		ExpiresAt: now.Add(-time.Second),
+	})
+	require.NoError(t, err)
+	freshTok, err := mintTransferToken(transferEntry{
+		UserID:    1,
+		TokenID:   1,
+		ServerID:  1,
+		Path:      "/srv/fresh",
+		Direction: transferDirDownload,
+		ExpiresAt: now.Add(5 * time.Minute),
+	})
+	require.NoError(t, err)
+
+	removed := gcExpiredTransferEntries(now)
+	require.Equal(t, 1, removed, "exactly one expired entry must be removed")
+
+	_, expiredStillThere := transferEntries.Load(expiredTok)
+	require.False(t, expiredStillThere, "expired entry must be gone after GC")
+	_, freshStillThere := transferEntries.Load(freshTok)
+	require.True(t, freshStillThere, "fresh entry must survive GC")
+
+	// 二次 GC 不应误删未过期项，也不应报告假阳性。
+	require.Equal(t, 0, gcExpiredTransferEntries(now), "second GC must be a no-op for non-expired entries")
+}