Generate simulation telemetry envelopes for Modal requests

[anth-volk]

Fixes #3404

Summary

• generate the internal _telemetry envelope alongside the existing _metadata payload for Modal simulation submissions
• include run_id, process_id, geography classification, config hash, requested timestamp, and traceparent when available
• propagate run_id through the Modal client response object and submission/error logs without regressing current bundle metadata behavior
• add fixtures and unit coverage for the new telemetry envelope flow

Validation

• uv run ruff check policyengine_api/libs/simulation_api_modal.py policyengine_api/services/economy_service.py tests/fixtures/libs/simulation_api_modal.py tests/fixtures/services/economy_service.py tests/unit/libs/test_simulation_api_modal.py tests/unit/services/test_economy_service.py
• uv run pytest --noconftest tests/unit/libs/test_simulation_api_modal.py

[codecov]

Codecov Report

❌ Patch coverage is 78.12500% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 73.06%. Comparing base (39d6550) to head (62a6096).
⚠️ Report is 6 commits behind head on master.

Files with missing lines	Patch %	Lines
policyengine_api/services/economy_service.py	77.41%	5 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3405      +/-   ##
==========================================
+ Coverage   72.97%   73.06%   +0.09%     
==========================================
  Files          56       56              
  Lines        2598     2629      +31     
  Branches      460      463       +3     
==========================================
+ Hits         1896     1921      +25     
- Misses        617      622       +5     
- Partials       85       86       +1     

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