fix: run Electron artifact builds in the bounded worker [CI SKIP]

docs/image-build-limits.md

@@ -15,6 +15,8 @@ settings or default builder selection are changed.
 ## Covered source paths
 
 - Admin app component image builds (including LMS FE/BE web images).
+- Admin Electron/AppImage jobs: dependency installation and packaging run in the
+  same bounded worker, with secret build configuration and a local artifact exporter.
 - Launcher backend image builds.
 - Woodpecker image-build steps for admin FE/BE, auth, platform gateway and manual.
 
@@ -54,7 +56,10 @@ other builders do not automatically use this worker. Those workflows must also
 be routed explicitly before claiming every image build on the server is limited.
 Do not let CI cleanup remove the shared builder after each job.
 
-Electron/npm builds outside Docker image builds are separate and unchanged.
+Admin Electron jobs have a 30-minute install/build timeout and a 4 GiB Node heap
+ceiling inside the aggregate 8 GiB worker limit. Git credentials and the admin
+API environment are not sent to the build context. No runtime image setting is
+required. The separate launcher-client Electron build path remains unchanged.
 This does not diagnose or guarantee prevention of power, hardware or kernel
 failures. Runtime service limits, deployment behavior and database migrations
 are not modified.