chore(ci): align workflow frontend-copy with Makefile frontend-build (#474)

PR #473 changed the Makefile `frontend-build` target to copy into
`web/frontend/dist/` and `touch web/frontend/dist/.gitkeep` (so the
`//go:embed all:frontend/dist` directive always has something to embed).
The release.yml and pr-build.yml "Copy frontend dist" steps still used
the older `cp -r frontend/dist web/frontend/` form.

Both forms place a real index.html under web/frontend/dist/ so release
artifacts were never broken, but the divergent forms are confusing and
the workflow steps did not recreate the tracked .gitkeep. This aligns
both workflows with the Makefile so there is a single canonical form.

Follow-up to #473. No functional change to release/CI artifacts.

Co-authored-by: Claude Code <noreply@anthropic.com>

Author: Dumbris

.github/workflows/pr-build.yml

@@ -176,8 +176,11 @@ jobs:
         shell: bash
         run: |
           rm -rf web/frontend
-          mkdir -p web/frontend
-          cp -r frontend/dist web/frontend/
+          mkdir -p web/frontend/dist
+          cp -r frontend/dist/. web/frontend/dist/
+          # Recreate the tracked .gitkeep so //go:embed all:frontend/dist
+          # always has something to embed (matches the Makefile frontend-build target).
+          touch web/frontend/dist/.gitkeep
 
       - name: Run tests (skip binary E2E tests - not compatible with cross-compilation)
         # Skip tests for Windows ARM64 (cross-compilation - can't run ARM64 binaries on AMD64 runner)

.github/workflows/release.yml

@@ -294,8 +294,11 @@ jobs:
         shell: bash
         run: |
           rm -rf web/frontend
-          mkdir -p web/frontend
-          cp -r frontend/dist web/frontend/
+          mkdir -p web/frontend/dist
+          cp -r frontend/dist/. web/frontend/dist/
+          # Recreate the tracked .gitkeep so //go:embed all:frontend/dist
+          # always has something to embed (matches the Makefile frontend-build target).
+          touch web/frontend/dist/.gitkeep
 
       - name: Import Code-Signing Certificates (macOS)
         if: matrix.goos == 'darwin'