Migrate to nmr script runner

[williamthorsen]

Problem

The repo uses a hand-rolled scripts/run-workspace-script.ts and custom utility scripts inherited from templates.node-monorepo. These are now superseded by @williamthorsen/nmr, which provides the same functionality as a shared package.

Context

• Migration guide: Write nmr migration guide for repos based on templates.node-monorepo node-monorepo-tools#82
• This repo has 3 script files to delete (no helpers/ directory, no sync-pnpm-version.ts)
• nmr 0.3.0 defaults match existing CI ordering (check:strict then build) — no config override needed
• fmt:all and fmt:sh are being added to nmr defaults (node-monorepo-tools#83) — omit from repo-specific scripts
• demo:catwalk is obsolete — remove it
• @williamthorsen/toolbelt.objects is only used in scripts being deleted — remove from root devDependencies

Solution

Follow the nmr migration guide (steps 1, 3–9; step 2 skipped since no config override is needed):

1. Install @williamthorsen/nmr as root devDependency
2. Reduce root package.json scripts to lifecycle hooks + repo-specific scripts:
   • postinstall: nmr report-overrides --quiet; nmr sync-pnpm-version
   • prepare: lefthook install
   • Repo-specific: agents:install, agents:install-launchers
   • Remove: preinstall, demo:catwalk, and all scripts nmr provides as defaults
3. Update workspace packages: remove ws script, remove default-matching scripts, keep genuine overrides (agents build, factory build/dev/etc.)
4. Replace consistency tests with runConsistencyChecks(import.meta.dirname)
5. Delete scripts/run-workspace-script.ts, scripts/assertIsPackageJson.ts, scripts/report-overrides.ts
6. Remove orphaned root devDep: @williamthorsen/toolbelt.objects
7. Update .agents/PROJECT.md

Acceptance criteria

• pnpm install completes (postinstall hook works)
• nmr ci passes
• nmr build succeeds per package
• nmr root:test passes (consistency checks via nmr)
• No references to run-workspace-script.ts remain
• No ws script in any workspace package.json
• @williamthorsen/toolbelt.objects removed from root devDependencies
• preinstall and demo:catwalk scripts removed