test: isolate Playwright output from development profiles

[Mat4m0]

What changed

Playwright writes Electron and Tools results into separate subdirectories. Starting a suite no longer clears unrelated development profiles or evidence under test-results/.

Why

The previous Electron default cleared the shared results directory. This was reproduced during native-rendering verification. CI now collects both suites from the same results root.

Invariant

Each suite owns only its disposable output directory. Both suites preserved an independent sentinel outside their directories.

Delivery

Targets main; first layer of the native-rendering stack. No application release is needed for this tooling fix.

Verification

Tools end-to-end suite: 42 passed. Focused Electron checks: four passed. Workflow policy, lint, and documentation-link checks passed.

• I kept this pull request focused.
• I ran the relevant checks.
• I did not add game binaries, credentials, diagnostics, or private traffic.
• I updated documentation when behavior or an invariant changed.