fix(build): build @loopover/contract in ui:build so a clean checkout can deploy

Cloudflare Workers Builds has failed on every recent commit, which is the
deploy path for loopover-ui — no GitHub Actions workflow runs `wrangler deploy`
(ui-deploy.yml only validates). Production has consequently been serving stale
code: #9574's `fleetAccuracy.basis` and #9594's anchor-payload auth exemption
both landed on main and neither is live.

The build command is `npm run build:cloudflare` -> `npm ci && npm run ui:build`.
`ui:build` runs `turbo run build --filter=@loopover/engine`, then `ui:openapi`,
whose `scripts/write-ui-openapi.ts` reaches `src/openapi/schemas.ts` and imports
`@loopover/contract/dist/public-api.js`. Nothing in that chain builds
`@loopover/contract` — `@loopover/engine` does not depend on it — so on a clean
checkout the import resolves to a directory that was never emitted:

  Error [ERR_MODULE_NOT_FOUND]: Cannot find module
    '/opt/buildhome/repo/node_modules/@loopover/contract/dist/public-api.js'
    imported from /opt/buildhome/repo/src/openapi/schemas.ts

It passes in `test:ci` only by accident of ordering: `npm run typecheck` runs
first, and the `//#typecheck` turbo task already carries an explicit
`@loopover/contract#build` edge — added for exactly this failure mode, and
documented in turbo.json as "the root package.json dependency does NOT create a
build edge for a root task". Cloudflare runs `ui:build` on its own, with no
typecheck ahead of it, so the incidental ordering never applies.

Adding the same edge to `ui:build`'s own turbo invocation, which is the level
that actually owns the dependency.

Verified against a genuinely clean tree (package dists and .tsbuildinfo files
removed, TURBO_FORCE=1 to defeat the shared worktree cache — the first two
attempts at reproducing this were masked by a stale tsbuildinfo and then by a
turbo cache replay): without this change `ui:build` exits 1 on the error above;
with it, exit 0 and both dist artifacts are emitted.

Author: JSONbored

package.json

@@ -59,7 +59,7 @@
     "lint:composite-actions": "node --experimental-strip-types scripts/lint-composite-actions.ts",
     "ui:dev": "npm run ui:preview",
     "ui:kit:build": "npm run build --workspace @loopover/ui-kit",
-    "ui:build": "npm run ui:kit:build && turbo run build --filter=@loopover/engine && npm run ui:openapi && npm --workspace @loopover/ui run build && npm --workspace @loopover/ui-miner run build",
+    "ui:build": "npm run ui:kit:build && turbo run build --filter=@loopover/engine --filter=@loopover/contract && npm run ui:openapi && npm --workspace @loopover/ui run build && npm --workspace @loopover/ui-miner run build",
     "ui:preview": "npm run ui:build && wrangler dev --config apps/loopover-ui/dist/server/wrangler.json --ip 127.0.0.1 --port 4173 --local",
     "ui:lint": "npm run ui:kit:build && npm --workspace @loopover/ui-kit run format:check && npm --workspace @loopover/ui run format:check && npm --workspace @loopover/ui run lint && npm --workspace @loopover/ui-miner run format:check && npm --workspace @loopover/ui-miner run lint",
     "ui:typecheck": "npm run ui:kit:build && npm --workspace @loopover/ui run typecheck && npm --workspace @loopover/ui-miner run typecheck",