feat: implementation of architectural impact analyzer utility

[UmmeHabiba1312]

Overview

This PR introduces a specialized Architectural Impact Analyzer to the Spec-Kit ecosystem. It enables developers to preview risks and complexity of a proposed change across all specifications before moving to the implementation phase.

Key Features

• Context-Aware Analysis: Dynamically scans .specify/memory (or default presets) to provide the AI with a holistic architectural view.
• Zero-Config Integration: Automatically inherits existing environment variables (AI_API_KEY, ANTHROPIC_API_KEY, AI_MODEL_ID) from the user's current CLI session no extra setup required.
• Provider Agnostic: Built on standard patterns to support OpenAI, Anthropic, and custom base URLs/models.
• Structured Reports: Generates professional CLI-native reports including complexity scores, estimated effort, and specific architectural risks.

Implementation Details

• scripts/impact_analyzer.py: The core analysis engine with smart path resolution and environment detection.
• templates/commands/preview.md: Native template that triggers the analyzer as a standard Spec-Kit command.
• Registry Updates: Fully integrated into specify_cli registry and Claude Code hints for a seamless user experience.

Fixes #2176

[UmmeHabiba1312]

Hi @mnriem,
I've just pushed a significant refactor to ensure this feature feels native to Spec-Kit. The analyzer now dynamically resolves paths (handling both project-specific .specify folders and default presets) and automatically inherits the existing AI environment context. This eliminates the need for redundant API key configurations and ensures a seamless UX. Ready for a deep dive review!

[mnriem]

Please deliver this as a community extension. See https://github.com/github/spec-kit/blob/main/presets/README.md?tab=readme-ov-file#extensions--add-new-capabilities

[UmmeHabiba1312]

I have refactored the contribution into a Community Preset following the scaffold/ pattern. The logic is now fully encapsulated within presets/community/architect-preview/ and I have removed all manual overrides from the core files.

This aligns with the new stacking architecture and ensures the core remains clean. Ready for final review.

@mnriem

[mnriem]

@UmmeHabiba1312 Appreciate you working through this. So we (the maintainers) are not the blockers for your extension we ask you to host it on your own GitHub repository as per https://github.com/github/spec-kit/blob/main/extensions/EXTENSION-PUBLISHING-GUIDE.md

[UmmeHabiba1312]

@mnriem I am closing this PR as I have moved the Architect Impact Previewer to a standalone repository per your suggestion.

I have submitted a new PR for the community catalog entry here: #2214

Thank you for guiding me towards the decentralized model!