feat: add architecture diagram for docs/ARCHITECTURE.md (issue #118)

[emberb170d]

Adds a mermaid architecture diagram showing the flow from CLI → templates.json → template + extensions merge → generated project. Addresses issue #118 (docs: add architecture diagram to docs/ARCHITECTURE.md).

Summary by CodeRabbit

• Documentation

  • Added an architecture overview diagram describing the project generation workflow, including templates, extensions, Git setup, and dependency installation.

• New Features

  • Standardized template formatting with shared editor configuration defaults.
  • Added Python 3.12 version settings across supported templates, helping ensure consistent development environments.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

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Run ID: 4cdf9417-4929-4b53-8477-8b2e37bf2259

📥 Commits

Reviewing files that changed from the base of the PR and between 7d73b4a and f8a28b3.

📒 Files selected for processing (1)

• docs/ARCHITECTURE.md

🚧 Files skipped from review as they are similar to previous changes (1)

• docs/ARCHITECTURE.md

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📝 Walkthrough

Walkthrough

The PR adds shared editor settings to six templates and Python 3.12 pinning to five templates. It also adds an architecture diagram that documents template merging, project generation, Git initialization, and dependency installation.

Changes

Template standards and architecture

Layer / File(s)	Summary
Template development defaults templates/*/.editorconfig, templates/*/.python-version	Six templates add shared editor formatting rules. Five templates add Python 3.12 version files.
Architecture generation flow docs/ARCHITECTURE.md	The architecture documentation adds a Mermaid flowchart for CLI input, registry resolution, template and extension merging, project creation, Git initialization, and dependency installation.

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related issues

• docs: add architecture diagram to docs/ARCHITECTURE.md #118: The issue requests the Mermaid architecture diagram added to docs/ARCHITECTURE.md.

Possibly related PRs

• Create-Python-App/cpa-templates#163: Adds overlapping .editorconfig and .python-version files across the templates.
• Create-Python-App/cpa-templates#162: Modifies the same template configuration files and adds related documentation.
• Create-Python-App/cpa-templates#154: Adds the same .python-version files to the five templates.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: adding an architecture diagram to docs/ARCHITECTURE.md.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
Inline comments:
In `@docs/ARCHITECTURE.md`:
- Around line 22-35: Update the Mermaid architecture diagram around the Git and
Install nodes to show their generation guards: indicate that Git initialization
is skipped when CPA_SKIP_GIT=1, and that uv sync requires pyproject.toml and is
skipped with --no-install. Keep the existing generation flow intact while making
both conditions visible on the relevant nodes or edges.

🪄 Autofix

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 32f070f9-960d-4b2a-adcd-ab4924cd521a

📥 Commits

Reviewing files that changed from the base of the PR and between 6986f9b and 7d73b4a.

📒 Files selected for processing (12)

• docs/ARCHITECTURE.md
• templates/celery-worker/.editorconfig
• templates/celery-worker/.python-version
• templates/cli-starter/.editorconfig
• templates/cli-starter/.python-version
• templates/django-api/.editorconfig
• templates/django-api/.python-version
• templates/fastapi-starter/.editorconfig
• templates/fastapi-starter/.python-version
• templates/mlops-sklearn-starter/.editorconfig
• templates/mlops-sklearn-starter/.python-version
• templates/uv-workspace-starter/.editorconfig

[ulises-jeremias]

The mermaid in ARCHITECTURE.md is enough for #118, but this PR is not merge-ready yet:

• Required L1/registry checks have not run (unstable).
• The branch still carries the .editorconfig / .python-version files from chore: add .editorconfig to all templates #152/chore: add .python-version to templates missing it #153, which already landed in chore: add .python-version and .editorconfig to all templates (fixes #152, #153) #159.

Please rebase onto current main, drop those already-merged files so the PR is diagram-only, restore a trailing newline on ARCHITECTURE.md if it disappeared, and let L1 re-run. Also retitle to docs: rather than feat:.