fix(desktop): disable method/marking/static ProGuard optimization

The smoke test discovered that ProGuard's method/marking/static pass
converts kmp-tor's AsyncFs.of() from instance to static. The JVM
then throws IncompatibleClassChangeError at launch because callers
still use invokevirtual.

Also updates smoke-test-desktop.yml trigger: runs on any PR touching
desktopApp/ (not just build config files).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.github/workflows/smoke-test-desktop.yml

@@ -1,20 +1,11 @@
-# ⚠️  WARNING: Before merging, change the trigger back to workflow_dispatch only.
-# The pull_request trigger is temporary so we can validate this workflow on the PR
-# and attach run results as proof-of-work. Production trigger should be:
-#
-#   on:
-#     workflow_dispatch:
-#     pull_request:
-#       paths:
-#         - 'desktopApp/build.gradle.kts'
-#         - 'desktopApp/compose-rules.pro'
-#         - '.github/workflows/smoke-test-desktop.yml'
-#
 name: Desktop Smoke Test
 
 on:
   workflow_dispatch:
   pull_request:
+    paths:
+      - 'desktopApp/**'
+      - '.github/workflows/smoke-test-desktop.yml'
 
 permissions:
   contents: read