feat: add GET /api/v2/agent-firewall/sessions/{id}/logs endpoint (#24816)

Add a `GET /api/v2/agent-firewall/sessions/{id}/logs` endpoint that
returns agent firewall audit logs for a given session, sorted by
sequence number ascending.

The endpoint supports `seq_after` and `seq_before` (exclusive bounds)
and `limit` query parameters. This enables the frontend to fetch exactly
the firewall events that fall between two AI Bridge interceptions within
a thread, as described in FR 4 of the Boundary/Bridge correlation RFC.

Authorization reuses the `boundary_log` RBAC resource (owner and auditor
can read; members cannot). Returns 404 for unauthorized users to avoid
leaking existence information.

The endpoint is enterprise-only, gated behind `FeatureBoundary`
entitlement, matching the session endpoint from #24814.

Depends on #24814

> [!NOTE]
> This PR was authored by Coder Agents.

coderd/coderd.go

@@ -1471,6 +1471,7 @@ func New(options *Options) *API {
 			r.Get("/", api.auditLogs)
 			r.Post("/testgenerate", api.generateFakeAuditLog)
 		})
+
 		r.Route("/files", func(r chi.Router) {
 			r.Use(
 				apiKeyMiddleware,