[TheGreatAxios]

Moves the designer's tools into @corbits-builder/tools-design: file_design_option logic and definition, the design check, and design tokens and tweaks (with their tests), plus the defineTool bundle createDesignTools({ failure }).

• The hub injects its failure helper, so logging stays in the hub and the package imports no hub internals.
• writeBundle and unpackDesign are not designer tools (the starter, live app and coder use them); they move to apps/hub/src/artifacts/design-bundle.ts.
• The bundle id stays @corbits-builder/artifacts/design-tools, so grant names are unchanged.

The package repeats the hub's tolerant artifact receipt schema (ArtifactReceipt.onDeepUndeclaredKey("ignore")); it collapses to one copy when the document tools move (CL-11881).

Stacked on #37. Closes CL-11883

Verification

• lint, format:check, typecheck, test (71 pass); packaged.test.ts builds the real workflow bundles.
• Old-vs-new comparison: id, requires, credentials, names, schema and description identical; error codes unchanged.
• Independent review bundled the designer entry: one design-check registry shared by the coding tools and the filing tool, as before.

[linear-code]

CL-11883

[corbits-triage]

Triage: Pass

No changes needed from you. A maintainer will review this pull request.

Stacked on #37: only this pull request's own changes were checked.

Notes:

• changes sensitive paths: locks: bun.lock

Triage will approve, request review.

[TheGreatAxios]

Closing: the decoupling plan on CL-11879 (adopt @corbits/artifacts with Builder rules in its write hook, run-scoped routes, tools that know nothing about projects or tenants) reshapes this package. It will be redone under that plan.