feat(FN-1318): rename CLI binary artifacts from kb to fn

- Update CLI build and runtime paths to emit and reference fn-named binaries across default and cross-target builds
- Adjust Bun binary bootstrap stubs and native patch temp/symlink prefixes to use fn naming consistently
- Update CI, release, and test-release workflows to validate and collect fn-prefixed artifacts
- Align CLI build and package config tests with fn binary expectations and add a patch changeset for @gsxdsm/fusion

.github/workflows/ci.yml

@@ -40,4 +40,4 @@ jobs:
         run: pnpm --filter @gsxdsm/fusion build:exe
 
       - name: Verify binary exists
-        run: test -f packages/cli/dist/kb
+        run: test -f packages/cli/dist/fn