Replace any-casts in command-registry with a typed command lookup

[alfonso-noriega]

WHY are these changes introduced?

packages/cli/src/command-registry.ts carried 7 eslint-disable @typescript-eslint/no-explicit-any suppressions: the lazy command loader returned Promise<any | undefined> and each external plugin branch indexed its command table through as any. The module also had no unit tests. Surfaced by the daily maintenance radar (suppression cleanup).

WHAT is this pull request doing?

• Types the loader against @oclif/core's Command class (CommandClass = typeof Command), matching the LazyCommandLoader contract in cli-kit ((id: string) => Promise<typeof Command | undefined>).
• Bridges the external plugin package tables (@shopify/cli-hydrogen, @oclif/plugin-commands, @oclif/plugin-plugins, @shopify/plugin-did-you-mean) through a single commandFromTable helper — one documented cast at the package boundary instead of four inline as any, since each package compiles against its own @oclif/core.
• Adds command-registry.test.ts covering manifest misses and the full-package fallback path (real imports, no mocks).
• Adds a @shopify/plugin-did-you-mean → src alias to the shared vitest config so the module under test resolves in vitest, same pattern as the existing @shopify/theme/@shopify/organizations aliases.

No runtime behavior change: the lookups and fallbacks are identical, only the types changed.

How to test your changes?

• pnpm vitest run packages/cli/src/command-registry.test.ts (3 tests)
• pnpm --filter @shopify/cli type-check && pnpm --filter @shopify/cli lint
• Sanity: pnpm shopify commands and pnpm shopify plugins still resolve through the full-package fallback; any app/theme command still loads per-file.

Checklist

• I've considered possible cross-platform impacts (Mac, Linux, Windows)
• I've considered possible documentation changes
• I've considered analytics changes to measure impact
• The change is user-facing — I've identified the correct bump type (patch for bug fixes · minor for new features · major for breaking changes) and added a changeset with pnpm changeset add

No changeset: internal refactor + tests, no user-visible change.