Integrate latest local community extensions

[bigsmartben]

Summary

Integrates the latest local community extension snapshots into this spec-kit checkout:

• Updates bundled arch to v1.2.1, replacing the legacy generate/reverse commands with the 10 split 4+1 view commands and schema-backed setup contract.
• Adds bundled intake at v0.1.2 and includes it in the default bundled init extensions.
• Updates catalog metadata, smoke checks, default integration inventories, and user-facing docs for the new command surface.
• Adds local community integration validation workflow/scripts.

Community submission metadata

Submission route: pr-template
Catalog type: extension
Source repository: https://github.com/bigsmartben/spec-kit-arch
Source version: v1.2.1
Source commit: 137adf067ae091b5b096a153876c8fe7cd8985b9
Download URL: https://github.com/bigsmartben/spec-kit-arch/archive/refs/tags/v1.2.1.zip

Additional source repository: https://github.com/bigsmartben/spec-kit-intake
Additional source version: v0.1.2
Additional source commit: bcda0aabadf12e2c9bf191ab1f35acfebb6ca5d6
Additional download URL: https://github.com/bigsmartben/spec-kit-intake/archive/refs/tags/v0.1.2.zip

Validation

• python scripts/community/validate_integration.py --repo-root .
• Targeted pytest: 11 passed, 2 skipped
• Full uv run pytest -q: 3773 passed, 165 skipped, 10 failed

Full-suite residual failures appear environment-specific on this Windows host:

• Symlink creation tests fail with WinError 1314 because the process lacks symlink privileges.
• Two preset wrap tests fail with UnicodeDecodeError from default GBK decoding while reading UTF-8 skill files.