Deprecate national-with-breakdowns dataset selectors

[anth-volk]

Fixes #3728.

Summary:

• Makes include_district_breakdowns a deprecated no-op in API v1 routes.
• Deprecates national-with-breakdowns, national-with-breakdowns-test, and national-with-datasets as no-op dataset aliases that normalize to default.
• Bumps the economy-impact cache schema so old cached responses do not mask the new district payload shape.

Merge dependencies:

• Requires Fix simulation deploy integration assertions policyengine-sim-api#618 to be fully merged before this PR merges.

Follow-up:

• Removal issue: Remove deprecated district breakdown request flags #3727

Verification:

• uv run ruff check on changed API v1 files
• uv run pytest tests/unit/services/test_economy_service.py tests/unit/routes/test_economy_dataset_validation.py tests/to_refactor/python/test_economy_budget_window_routes.py -q

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 79.89%. Comparing base (446d995) to head (1735f68).
⚠️ Report is 19 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3726      +/-   ##
==========================================
+ Coverage   79.72%   79.89%   +0.16%     
==========================================
  Files          70       70              
  Lines        4326     4332       +6     
  Branches      807      807              
==========================================
+ Hits         3449     3461      +12     
+ Misses        657      652       -5     
+ Partials      220      219       -1     

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