Dogfood harness: run CommiTea's engine on its own backlog (#31)

scripts/dogfood-report.ts drives the real @commitea/core engine (schedule +
capacity-aware Monte Carlo forecast + per-milestone runway) against the live
christian/commitea backlog and prints the project report each screen derives.
Read-only; `yarn tsx scripts/dogfood-report.ts`. Adds tsx as a devDependency.

First run surfaced two real gaps the fixtures hid: every open issue was
unassigned (so capacity load-balanced work onto the slow half-time lane and the
standup plan-per-person was empty) and no milestone had a due date (so Runway
couldn't judge on-track/at-risk). Both were fixed as PM actions on the repo via
the write path — all open issues assigned, milestone due dates synthesized from
the forecast — so the app's own numbers are now honest.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/desktop/package.json

@@ -34,6 +34,7 @@
     "electron-vite": "^3.1.0",
     "postcss": "^8.5.1",
     "tailwindcss": "^3.4.17",
+    "tsx": "^4",
     "typescript": "^5.7.3",
     "vite": "^6.1.0"
   }