feat(cli): remove framework config and simplify build command

[matthewvolk]

What/Why?

The framework configuration concept (catalyst | nextjs) is no longer needed. The CLI will only be installed when using native hosting, so the nextjs framework path is a dead code path. This PR removes it entirely and simplifies the build command to always call buildCatalystProject() directly.

Changes

• project-config.ts — Remove framework from ProjectConfigSchema and its Conf schema definition
• build.ts — Remove .allowUnknownOption(), [next-build-options...] argument, --framework option, and the nextjs branch in the action handler; remove unused existsSync import
• project.ts — Remove config.set('framework', 'catalyst') from create and link actions
• Tests — Remove all framework-related assertions, mocks, and test cases across build.spec.ts, project.spec.ts, and project-config.spec.ts

Testing

• vitest run — all tests pass (2 pre-existing failures in index.spec.ts and version.spec.ts are unrelated)
• eslint . — clean
• tsc --noEmit — clean

Migration

The framework key in .bigcommerce/project.json is no longer read or written. Existing config files with this key will be silently ignored by conf.

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Project	Deployment	Actions	Updated (UTC)
catalyst	Ready	Preview, Comment	Feb 20, 2026 5:22pm

[changeset-bot]

🦋 Changeset detected

Latest commit: 3970f55

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@bigcommerce/catalyst	Minor

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