Eval runner: send the prompt on stdin; add a-empty results

On Windows a multi-line argv prompt is cut at its first newline, which
also dropped the permission flags. The a-empty eval now passes every
check, including the page check on the page the skill built.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/evals/results/a-empty.json

@@ -0,0 +1,24 @@
+{
+  "fixture": "a-empty",
+  "passed": true,
+  "checks": {
+    "frontend reported correctly": true,
+    "asks /colou?r/": true,
+    "asks /desktop|web/": true,
+    "asks /section/": true,
+    "never asks /\\bkeep\\b|restyle/": true,
+    "exactly one page built": true,
+    "no placeholders left": true,
+    "custom palette applied": true,
+    "page check passes": true
+  },
+  "page_check": [
+    "22 passed in 17.68s"
+  ],
+  "files": [
+    "README.md",
+    "dashboard\\bridge.py",
+    "dashboard\\dashboard.html"
+  ],
+  "reply": "Dashboard ready ah iruku. Sample data la run aagudhu, headless browser la check panniten.\n\n| Item | Details |\n|---|---|\n| Files | `dashboard/dashboard.html`, `dashboard/bridge.py` (PyQt6 desktop host) |\n| Theme | Custom `#7a3cff`. Contrast check 10/10 PASS, colour-ah change panna thevai illa. Dark mode la button colour konjam light ah `#8248ff` nu irukum. Background innum template oda sky-blue gradient dhaan, purple accents mattum dhaan maarinadhu. |\n| Sections | Core mattum: sidebar, top bar, dark toggle, status dot, KPI cards, donut, run panel, report table. Optional edhuvum add pannala. |\n| Data | `SAMPLE_DATA = true`. Project la bot illa. |\n\n**Check results (Playwright, browser la open panni):**\n- KPI: 6 total / 3 completed / 1 in progress / 1 not completed. Donut legend la 4 rows.\n- Run: 4/4 steps done, 5 log lines, status \"Completed\".\n- Report: 4/4 rows la status pill varudhu.\n- Light, dark, 800px width moonum sariya varudhu. Script errors 0, `{{` placeholders 0.\n- **UNVERIFIED:** `bridge.py` la irukura PyQt window-ah naan open pannala. Adhu real ah run aagudhanu check pannala.\n\n**Bot wire pannumbodhu:**\n- Bot indha events anuppanum: `status`, `step`, `log`, `dashboard_data`, `report_data`.\n- `bridge.py` la `BOT_CMD` (ippo `bot` nu placeholder), `STEP_MARKERS`, `FRIENDLY_RULES` set pannunga.\n- Apram `SAMPLE_DATA = false` panni, SAMPLE block-ah delete pannunga.\n\n**Also noticed:** steps (`Initializing \u2192 Login \u2192 Process items \u2192 Completed`) and report columns (Item/Batch/Status) placeholder dhaan, ungaloda real bot stages vandha maathanum.\n\nFRONTEND: none\nQUESTIONS: Which colours: Tebra Sky, Superbill Ember, or Custom (one brand hex)? | Desktop or web? | Which optional sections: checkpoint tracker, admin/roles screen, login page, or none?"
+}