Local Dev: offline template override (SPECIFY_TEMPLATE_ZIP) and consolidate development docs

[danwashusen]

Summary

• Introduces an offline/local template flow via SPECIFY_TEMPLATE_ZIP and adds ignore rules for
  generated artifacts.
• Consolidates and expands Local Development documentation into a single guide.

Included commits

• 9c8cea9: Add .gitignore rules, document local build/install steps, implement SPECIFY_TEMPLATE_ZIP
• eff3c72: Refactor build/development instructions to docs/local-development.md; update CONTRIBUTING
  and README

What changed

• CLI
  • Add SPECIFY_TEMPLATE_ZIP support to bypass GitHub download and use a local template ZIP, with
    safe cleanup behavior.
    • src/specify_cli/init.py:548
    • src/specify_cli/init.py:559
• Docs
  • Move “Development workflow” content into a dedicated Local Development guide and expand with an
    offline packaging flow:
    • docs/local-development.md:1
    • docs/local-development.md:96
    • docs/local-development.md:121
  • Point CONTRIBUTING to the Local Development guide:
    • CONTRIBUTING.md:39
  • Link README to the guide (ToC + Learn More):
    • README.md:26
    • README.md:254
• Repo hygiene
  • Ignore local build outputs:
    • .gitignore:1

How to use (quick)

• Build local templates:
  • Linux:
    • chmod +x .github/workflows/scripts/create-release-packages.sh && .github/workflows/scripts/
      create-release-packages.sh v0.0.1 && chmod -x .github/workflows/scripts/create-release-packages.sh
  • macOS (Docker):
    • docker run --rm -it -v "$PWD":/w -w /w ubuntu:24.04 bash -lc "apt-get update && apt-get
      install -y zip && chmod +x .github/workflows/scripts/create-release-packages.sh && .github/workflows/
      scripts/create-release-packages.sh v0.0.1 && chmod -x .github/workflows/scripts/create-release-
      packages.sh"
• Run CLI against a local ZIP:
  • SPECIFY_TEMPLATE_ZIP=/abs/path/spec-kit-template--<script>-v0.0.1.zip uvx --refresh --no-
    cache --from /abs/path/to/spec-kit specify init --here --ai --script <script> --ignore-agent-
    tools

Why

• Enables fully offline testing, avoids API rate limits/corporate proxy issues, and speeds iteration
  on template changes.
• Reduces docs duplication between CONTRIBUTING and user-facing docs.

Verification

• Build a ZIP with the packaging script; confirm artifacts are produced and git-ignored.
• Run init with SPECIFY_TEMPLATE_ZIP; confirm the project initializes from the local archive and the
  file is not deleted on cleanup.
• Confirm README and CONTRIBUTING links resolve to docs/local-development.md.

Impact

• Backwards compatible; default behavior unchanged when SPECIFY_TEMPLATE_ZIP is not set.
• Documentation improvements only outside of the env-var feature.