Generate CARLA blueprints dynamically

[lola831]

Description

This PR generates CARLA blueprints dynamically (per CARLA version).

-snapshot_blueprints.py: connects to CARLA, collects blueprint IDs and bounding-box dimensions for the running server version, categorizes them for Scenic, and writes tools/carla/snapshots/blueprints_<VERSION>.json.

-make_blueprints.py: reads all snapshot JSONs, sorts/normalizes them, and regenerates src/scenic/simulators/carla/blueprints.py.

-Generated blueprints.py: selects the best-matching snapshot for the installed CARLA version and exposes ids, dims, and helper functions.

-Handles versions that lack certain categories (e.g., CARLA 0.10.0 has no bicycles).

-Uses measured dimensions when available; otherwise falls back to defaults.

-Adds vanModels and busModels categories based on CARLA’s base_type.

Issue Link

N/A

Checklist

• I have tested the changes locally via pytest and/or other means
• I have added or updated relevant documentation
• I have autoformatted the code with black and isort
• I have added test cases (if applicable)

Additional Notes

N/A

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.65%. Comparing base (cbc265d) to head (f6a139a).
⚠️ Report is 6 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #401      +/-   ##
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- Coverage   89.70%   89.65%   -0.06%     
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  Files          48       48              
  Lines       13190    13190              
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- Hits        11832    11825       -7     
- Misses       1358     1365       +7     

see 5 files with indirect coverage changes

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[dfremont]

Looks good in general. Besides some minor comments above, my only suggestion is that since blueprints.py is now very long and difficult to read, let's try splitting it into two files. The non-autogenerated part can stay in blueprints.py, but let's move the giant _IDS and _DIMS dictionaries into a separate _blueprintData.py module and then do from _blueprintData import _IDS, _DIMS. The make_blueprints.py script can then just generate _blueprintData.py.

[lola831]

@dfremont Thanks for the review. I split out _IDS / _DIMS into _blueprintData.py and left helpers in blueprints.py as suggested. Also addressed all the other review comments in the latest commits.

[dfremont]

Looks good, thanks Lola!