feat(project): scaffold add runtime handler

[Hweinstock]

Problem

add runtime is missing.

Solution

• add support for project add runtime mostly mirroring the schema shapes.
• support two modes template and byo (import OOS here). We then use this input schema to scaffold the project, and resolve the config that goes into agentcore.json (to be implemented).
• new template flag describes templates like strands-python, which can be adjusted with flags (ex. --build Container, or --protocol mcp, with defaults for each template. This will keep us flexible to support more templates in the future.

Testing

• added unit tests for handler parsing, with implementation details to be filled in.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 99.63370% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 97.08%. Comparing base (2dba459) to head (473c989).
⚠️ Report is 6 commits behind head on refactor.

Files with missing lines	Patch %	Lines
src/handlers/project/add/runtime/index.ts	99.52%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##           refactor    #2035      +/-   ##
============================================
+ Coverage     97.04%   97.08%   +0.04%     
============================================
  Files           370      372       +2     
  Lines         22287    22559     +272     
============================================
+ Hits          21628    21902     +274     
+ Misses          659      657       -2     

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