Add some improvements to the valuset ingestion flow

[fzhao99]

PULL REQUEST

Summary

Some improvements / tests for the valueset ingestion flow in order to prepare for future use of this seeding process.

• Adds fixtures for VSAC and the eRSD for use in integration tests
• Adds a mocking harness for the integration tests / a basic check that the number of inserted tests in a mocking test run matches the expected fixture values
  • Will expand this in followup PR's that actually assert on the state of the underlying DB, but wanted to get this harness in so the PR doesn't swell
• Adds some basic error handling for the frontend page that errors when something goes wrong, as well as links to the docs in cases where we know the error cause.
• Figured out (at least locally) the issue with the deployment docs

API Key isn't set (per the interaction with California)

Screen.Recording.2025-08-27.at.9.mp4

Unauthorized error message

Screen.Recording.2025-08-27.at.11.44.59.AM.mov

Related Issue

Fixes #787, #808, and #801

Additional Information

Anything else the review team should know?

Checklist

• Descriptive Pull Request title
• Link to relevant issues
• Provide necessary context for design reviewers
• Ensure test coverage is above agreed upon threshold
• Update documentation

[codecov-commenter]

Codecov Report

❌ Patch coverage is 65.60847% with 65 lines in your changes missing coverage. Please review.
✅ Project coverage is 68.96%. Comparing base (5def99b) to head (133ff3d).

Files with missing lines	Patch %	Lines
src/app/backend/seeding/service.ts	51.28%	19 Missing ⚠️
src/app/backend/db-creation/service.ts	81.66%	11 Missing ⚠️
...s)/queryBuilding/querySelection/QuerySelection.tsx	52.63%	9 Missing ⚠️
...eryBuilding/querySelection/EmptyQueriesDisplay.tsx	36.36%	7 Missing ⚠️
e2e/utils.ts	28.57%	5 Missing ⚠️
...)/queryBuilding/querySelection/QueryRepository.tsx	50.00%	4 Missing ⚠️
src/app/backend/db-creation/lib.ts	80.00%	4 Missing ⚠️
src/app/backend/query-building/service.ts	75.00%	4 Missing ⚠️
src/app/backend/db/decorators.ts	50.00%	1 Missing ⚠️
src/app/constants.ts	80.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #809      +/-   ##
==========================================
+ Coverage   66.17%   68.96%   +2.79%     
==========================================
  Files         122      122              
  Lines        6587     6645      +58     
  Branches     1641     1654      +13     
==========================================
+ Hits         4359     4583     +224     
+ Misses       2215     2051     -164     
+ Partials       13       11       -2     

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