[DTrim99]

Fixes #3927

Summary

• This is the policyengine-api part of Allow US calculations in 2036 #3926: it lets US users pick 2036.
• policyengine_api/country.py: adds dict(name=2036, label="2036") to the US time_period options. The app's year picker, date ranges and budget-window starts all read this list. The UK is unchanged (2024–2030).
• policyengine_api/data/v2/catalog/extraction.py: METADATA_TIME_PERIODS["us"] becomes range(2036, 2021, -1).
• docs/canonical-spm.md: the artifact horizon becomes 2022–2036.

Draft until the bundle with a 2036 SPM forecast is ready.

• The canonical SPM forecast in the current bundle covers 2022–2035. A 2036 request fails with SPM_YEAR_UNAVAILABLE.
• Merge this in the same release as the PolicyEngine bundle update that carries spm-calculator 1.1.0 and its 2022–2036 forecast. Merging earlier would show 2036 in the app while every 2036 run fails.
• The v2 catalog stores the year list per published model version, and publication reconciliation compares staged and stored lists. So the new list should go out with a new bundle version.

Budget windows already allow end years through 2099 (BUDGET_WINDOW_MAX_END_YEAR). The worker reads its year boundary from the installed SPM provider. Neither needs a change here.

The SPM tests that use 2036 as an unavailable year (test_spm_settings.py, test_spm_year_worker_polling.py, test_budget_window_cache.py) run on mocked forecasts with years=(2022, 2035). They don't depend on the installed artifact, so they're unchanged. test_country_spm.py does run against the installed bundle, so its year outside the forecast moves from 2036 to 2037. 2037 is outside both the current and the 2036 forecast, so those tests pass before and after the bundle bump.

Rebased onto master on 2026-10-26. The 2036 entry now uses master's dict-literal style in country.py.

Testing

• ruff format and ruff check are clean on the changed files.
• No unit test pins the US year list. I didn't run the suite locally; CI covers it.
• After the bundle bump, on staging:
  • GET /us/metadata lists 2036.
  • A national 2036 economy run completes, with "2036" in its SPM receipt.
  • budget_window:2027:10 completes.
  • 2037 still returns SPM_YEAR_UNAVAILABLE.

🤖 Generated with Claude Code

https://claude.ai/code/session_01LqCGPgxDukji8Bhs57c5rH

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 87.79%. Comparing base (a26e969) to head (a9907ba).

Additional details and impacted files

@@             Coverage Diff             @@
##           master    #3928       +/-   ##
===========================================
+ Coverage   50.96%   87.79%   +36.83%     
===========================================
  Files         242      258       +16     
  Lines       14527    15950     +1423     
  Branches     2334     2621      +287     
===========================================
+ Hits         7403    14003     +6600     
+ Misses       6501     1280     -5221     
- Partials      623      667       +44     

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