fix(web): follow the agents scene part rename in the compiler test

[wgqqqqq]

What is broken

Frontend Build has been red on 1.0.0-explore since bdbc6cb, and the failure is in the test rather than in the product:

AppearancePackageValidationError: Appearance package validation failed with 1 issue:
scene agents:
  - [UNKNOWN_PART] scenes.agents.parts.coreGrid: Unknown part coreGrid

That commit restructured the agents scene's part list -- anchorBar, harnessGrid and coreGrid gave way to harnessPresentation and catalogGrid, and AgentsScene.tsx moved to data-bf-part="catalogGrid" with it. AppearanceCompiler.test.ts was not carried along: it still authors its package against coreGrid, so the validator rejects the part and compile throws before a single assertion in the case runs.

The fix

Two occurrences renamed to catalogGrid. The case is about a scene part reaching the compiled selector, not about which part it happens to be, so it follows the scene rather than the descriptor regaining a part nothing draws.

Not included

src/crates/assembly/core/builtin_skills/create-bitfun-skin/references/appearance-registry.json still carries the pre-rename coreGrid too. Nothing in CI validates that snapshot, SKILL.md says not to hand-edit it, and scripts/sync_registry.py is what regenerates it -- so it is left for whoever owns that skill.

Verification

• Reproduced first on a clean 1.0.0-explore checkout: 1 failed | 14 passed
• After the change, that file is 15 passed
• pnpm --dir src/web-ui run test:run: 523 files, 3835 tests, 0 failures
• pnpm run lint:web: clean