feat(dogfood): integrate and document complete v0 loop

Extend the smoke harness with Orb execution-plane preflight probes
(Docker, OpenCode, Gitea reachability/creds/PR-creation, repository
writable) that report BLOCKED with exact reasons when dependencies are
absent. Add scripts/orb-project-run.ts as the missing connection point
between OrbProjectManager and the Orb/Git lifecycle. Write
docs/DOGFOOD_V0.md covering architecture, startup order, env vars,
local/server flows, demo procedure, health checks, failure recovery,
cleanup, known limitations, and next milestones.

The smoke harness now runs 18 preflight checks across control-plane and
Orb execution-plane layers, all with stable markers and sanitized JSON
reports. The orb:run script (ORB_RUN=1) drives one issue through the
full Orb project-manager lifecycle.

package.json

@@ -60,7 +60,8 @@
     "docs:update": "bun run scripts/update-docs.ts",
     "subtree": "bun run scripts/subtree.ts",
     "fix": "ultracite fix",
-    "orb:proof": "bun run scripts/orb-proof.ts"
+    "orb:proof": "bun run scripts/orb-proof.ts",
+    "orb:run": "bun run scripts/orb-project-run.ts"
   },
   "dependencies": {},
   "devDependencies": {