[management,proxy] Agent network: per-account LLM gateway (policy, metering, multi-provider) (#6555)

* [agent-network] Shared proto, OpenAPI schema, and generated types

* [agent-network] Management: store, manager, synthesizer, policy engine, provider catalog, HTTP/gRPC API

Adds the account-scoped agent-network module: provider/policy/budget CRUD and
store, the reverse-proxy service synthesizer, policy selection + limit
enforcement, the provider catalog (incl. Vertex AI and AWS Bedrock entries),
and the management HTTP + proxy gRPC surfaces.

* [management] Fix agent-network proxy-peer fan-out on affected-peer recompute

The affected-peers resolver loaded only persisted reverse-proxy services, but
agent-network services are synthesized on demand and never persisted. As a
result the embedded proxy peer was never folded into the affected set when a
client's group changed, so the proxy received no network-map update for a newly
authorised client and rejected its handshake until a full resync (restart).

loadProxyServices now merges the synthesized agent-network services (injected
via a registration hook to avoid an import cycle), so proxy peers learn newly
authorised clients immediately.

* [proxy] Reverse-proxy middleware framework, chain, and request plumbing

The per-target middleware chain (slots, dispatcher, mutation gate, metadata
merger), body capture, access-log terminal sink, and the proxy wiring that
builds + runs chains for synthesized agent-network services.

* [proxy] LLM parsers, pricing, and builtin middlewares (OpenAI, Anthropic, Vertex AI, AWS Bedrock)

Request/response parsers and SSE/event-stream metering, the embedded pricing
table, and the builtin middleware set: request parser, router, policy
limit-check/record, cost meter, guardrail, identity inject, response parser.
Includes the path-routed providers — Google Vertex AI (keyfile:: service-account
OAuth minting) and AWS Bedrock (bearer auth, invoke/converse/streaming, optional
/bedrock prefix) — plus the Models allowlist and unmeterable-publisher deny.

* [proxy] IPv6 in-place apply and TCP accept-loop hardening on netstack listeners

* [agent-network] End-to-end test suite, module docs, and deployment preset

* [agent-network] Fix codespell typos and exclude false positives

- labelgen word pool: vermillion -> vermilion, racoon -> raccoon.
- codespell ignore list: add flate (Go compress/flate package), recordin
  (a test-local identifier), and unparseable (a valid alternative spelling used
  consistently across identifiers + a metadata-value constant).

* [management] Set LastSeen on injected proxy peer in realstack test (MySQL strict-mode)

The injected embedded proxy peer had a PeerStatus with a zero LastSeen, which
serializes to '0000-00-00' and is rejected by MySQL in strict mode (SQLite
tolerates it). Set LastSeen to a valid time so SaveAccount succeeds on both
engines.

* [agent-network] Remove e2e shell-script suite from this branch

The end-to-end shell scripts under scripts/e2e/ are maintained in a separate
testing suite and are not part of this change set.

* [agent-network] Polish module docs: remove internal review scaffolding, fix links, verify diagrams

Strip PR-review framing, commit references, absolute paths, and stale internal
references from the agent-network module docs; fix broken relative links; verify
all diagrams against the current architecture. Remove the internal AI-reviewer
prompt file.

* [management] Refine session expiration handling to support 3-state encoding for SSO deadlines

* [agent-network] Relocate agentnetwork package to internals/modules

Move management/server/agentnetwork (and its catalog/, labelgen/, types/
subpackages) to management/internals/modules/agentnetwork, alongside the
reverse-proxy module, and rewrite all importers. Pure relocation: package names,
the synthesizer + affectedpeers registration hook, and store access (shared
store.Store) are unchanged, so no import cycle is introduced (affectedpeers
still depends only on the agentnetwork/types leaf).

* [agent-network] Co-locate HTTP handlers in the module (RegisterEndpoints)

Move the agent-network HTTP handlers from server/http/handlers/agentnetwork into
the module at internals/modules/agentnetwork/handlers (package handlers) and
rename the entrypoint AddEndpoints -> RegisterEndpoints, matching the
reverse-proxy module convention. Wiring in http/handler.go updated accordingly.

management/server/http/handler.go

@@ -23,6 +23,8 @@ import (
 	idpmanager "github.com/netbirdio/netbird/management/server/idp"
 
 	"github.com/netbirdio/netbird/management/internals/controllers/network_map"
+	"github.com/netbirdio/netbird/management/internals/modules/agentnetwork"
+	agentnetworkhandlers "github.com/netbirdio/netbird/management/internals/modules/agentnetwork/handlers"
 	"github.com/netbirdio/netbird/management/internals/modules/zones"
 	zonesManager "github.com/netbirdio/netbird/management/internals/modules/zones/manager"
 	"github.com/netbirdio/netbird/management/internals/modules/zones/records"
@@ -59,7 +61,7 @@ import (
 )
 
 // NewAPIHandler creates the Management service HTTP API handler registering all the available endpoints.
-func NewAPIHandler(ctx context.Context, router *mux.Router, accountManager account.Manager, networksManager nbnetworks.Manager, resourceManager resources.Manager, routerManager routers.Manager, groupsManager nbgroups.Manager, LocationManager geolocation.Geolocation, authManager auth.Manager, appMetrics telemetry.AppMetrics, permissionsManager permissions.Manager, settingsManager settings.Manager, zManager zones.Manager, rManager records.Manager, networkMapController network_map.Controller, idpManager idpmanager.Manager, serviceManager service.Manager, reverseProxyDomainManager *manager.Manager, reverseProxyAccessLogsManager accesslogs.Manager, proxyGRPCServer *nbgrpc.ProxyServiceServer, trustedHTTPProxies []netip.Prefix, rateLimiter *middleware.APIRateLimiter, isValidChildAccount middleware.IsValidChildAccountFunc) (http.Handler, error) {
+func NewAPIHandler(ctx context.Context, router *mux.Router, accountManager account.Manager, networksManager nbnetworks.Manager, resourceManager resources.Manager, routerManager routers.Manager, groupsManager nbgroups.Manager, LocationManager geolocation.Geolocation, authManager auth.Manager, appMetrics telemetry.AppMetrics, permissionsManager permissions.Manager, settingsManager settings.Manager, zManager zones.Manager, rManager records.Manager, networkMapController network_map.Controller, idpManager idpmanager.Manager, serviceManager service.Manager, reverseProxyDomainManager *manager.Manager, reverseProxyAccessLogsManager accesslogs.Manager, proxyGRPCServer *nbgrpc.ProxyServiceServer, trustedHTTPProxies []netip.Prefix, rateLimiter *middleware.APIRateLimiter, isValidChildAccount middleware.IsValidChildAccountFunc, agentNetworkManager agentnetwork.Manager) (http.Handler, error) {
 
 	// Register bypass paths for unauthenticated endpoints
 	if err := bypass.AddBypassPath("/api/instance"); err != nil {
@@ -124,6 +126,9 @@ func NewAPIHandler(ctx context.Context, router *mux.Router, accountManager accou
 	zonesManager.RegisterEndpoints(router, zManager)
 	recordsManager.RegisterEndpoints(router, rManager)
 	idp.AddEndpoints(accountManager, router)
+	if agentNetworkManager != nil {
+		agentnetworkhandlers.RegisterEndpoints(agentNetworkManager, router)
+	}
 	instance.AddEndpoints(instanceManager, accountManager, router)
 	instance.AddVersionEndpoint(instanceManager, router)
 	if serviceManager != nil && reverseProxyDomainManager != nil {