chore: create local impact-analysis action wrapper and update ci.yml reference

[arii]

Description

Create a local wrapper for the impact analysis action inside tech-dancer. This represents Phase 1.4 of the submodule decoupling strategy.

Workflows must avoid direct submodule paths to allow for easy migration away from the submodule layout.

Proposed Changes

1. Create .github/actions/impact-analysis/action.yml in the tech-dancer repository.
2. Mirror the inputs and structure of setup-workspace's wrapper, routing directly to ./boomtick-pkg/mcp/actions/impact-analysis.
3. Update ci.yml (line 274) to change:
   uses: ./boomtick-pkg/mcp/actions/impact-analysis
   to:
   uses: ./.github/actions/impact-analysis

Verification Checklist

• Verify: Trigger ci.yml via workflow_dispatch on the feature branch → confirm the impact-analysis job completes successfully using the wrapper.