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>

go.mod

@@ -22,11 +22,13 @@ require (
 	github.com/libdns/he v1.2.2
 	github.com/libdns/libdns v1.1.1
 	github.com/miekg/dns v1.1.72
+	github.com/modelcontextprotocol/go-sdk v1.6.1
 	github.com/nezhahq/libdns-tencentcloud v0.0.0-20250501081622-bd293105845a
 	github.com/ory/graceful v0.2.0
 	github.com/oschwald/maxminddb-golang v1.13.1
 	github.com/patrickmn/go-cache v2.1.0+incompatible
 	github.com/robfig/cron/v3 v3.0.1
+	github.com/sqids/sqids-go v0.4.1
 	github.com/stretchr/testify v1.11.1
 	github.com/swaggo/files v1.0.1
 	github.com/swaggo/gin-swagger v1.6.1
@@ -34,6 +36,7 @@ require (
 	github.com/tidwall/gjson v1.19.0
 	golang.org/x/crypto v0.52.0
 	golang.org/x/exp v0.0.0-20260508232706-74f9aab9d74a
+	golang.org/x/mod v0.36.0
 	golang.org/x/net v0.55.0
 	golang.org/x/oauth2 v0.36.0
 	golang.org/x/sync v0.20.0
@@ -75,6 +78,7 @@ require (
 	github.com/goccy/go-yaml v1.19.2 // indirect
 	github.com/golang-jwt/jwt/v4 v4.5.2 // indirect
 	github.com/golang/snappy v1.0.0 // indirect
+	github.com/google/jsonschema-go v0.4.3 // indirect
 	github.com/jinzhu/inflection v1.0.0 // indirect
 	github.com/jinzhu/now v1.1.5 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
@@ -93,7 +97,8 @@ require (
 	github.com/quic-go/qpack v0.6.0 // indirect
 	github.com/quic-go/quic-go v0.59.1 // indirect
 	github.com/rogpeppe/go-internal v1.14.1 // indirect
-	github.com/sqids/sqids-go v0.4.1 // indirect
+	github.com/segmentio/asm v1.1.3 // indirect
+	github.com/segmentio/encoding v0.5.4 // indirect
 	github.com/tidwall/match v1.2.0 // indirect
 	github.com/tidwall/pretty v1.2.1 // indirect
 	github.com/tidwall/sjson v1.2.5 // indirect
@@ -104,12 +109,12 @@ require (
 	github.com/valyala/gozstd v1.24.0 // indirect
 	github.com/valyala/histogram v1.2.0 // indirect
 	github.com/valyala/quicktemplate v1.8.0 // indirect
+	github.com/yosida95/uritemplate/v3 v3.0.2 // indirect
 	github.com/youmark/pkcs8 v0.0.0-20240726163527-a2c0da244d78 // indirect
 	go.mongodb.org/mongo-driver/v2 v2.6.0 // indirect
 	go.yaml.in/yaml/v2 v2.4.4 // indirect
 	go.yaml.in/yaml/v3 v3.0.4 // indirect
 	golang.org/x/arch v0.27.0 // indirect
-	golang.org/x/mod v0.36.0 // indirect
 	golang.org/x/sys v0.45.0 // indirect
 	golang.org/x/text v0.37.0 // indirect
 	golang.org/x/time v0.15.0 // indirect