Prevent duplicate inserts for canonical/reference rows

[dgee2]

Summary

• normalize ingredient unit-id payloads before canonical comparison
• reuse an existing ingredient row when the same name resolves to the same effective unit set
• block mismatched canonical redefinitions before insert and add unit/integration coverage for reuse behavior

Testing

• dotnet test --project .\backend\MenuApi.Tests\MenuApi.Tests.csproj
• dotnet test --project .\backend\MenuApi.Integration.Tests\MenuApi.Integration.Tests.csproj

Closes #978

[Copilot]

Pull request overview

This PR updates ingredient creation so canonical ingredient rows are reused instead of duplicated when the same ingredient name resolves to an equivalent effective unit-id set, and it rejects attempts to redefine an existing canonical name with a different unit set.

Changes:

• Normalize/deduplicate UnitIds at the service boundary before repository calls.
• Add repository lookup-before-insert logic to reuse equivalent existing ingredients (and throw on mismatched redefinitions).
• Add unit + integration test coverage for normalization and reuse behavior, plus squad documentation/decision records.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
backend/MenuApi/Services/IngredientService.cs	Normalizes/deduplicates incoming UnitIds before calling the repository.
backend/MenuApi/Repositories/IngredientRepository.cs	Implements lookup-by-name, equivalent-unit-set reuse, and mismatched redefinition rejection; refactors mapping.
backend/MenuApi.Tests/Services/IngredientServiceTests.cs	Unit test ensuring service-level UnitIds deduping before repository call.
backend/MenuApi.Tests/Repositories/IngredientRepositoryTests.cs	Repository tests covering reuse of equivalent canonical rows and rejection of redefinitions.
backend/MenuApi.Integration.Tests/IngredientIntegrationTests.cs	Integration test ensuring repeated equivalent creates return the same canonical row (same ID).
.squad/skills/canonical-reference-row-reuse/SKILL.md	Documents the canonical/reference row reuse pattern (normalization + reuse + reject redefinition).
.squad/decisions/inbox/basher-issue-978.md	Records the decision for issue #978 and scope rationale for POST /api/ingredient.
.squad/agents/basher/history.md	Adds project/agent history notes including where coverage for canonical reuse lives.

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[dgee2]

Danny review: approve. This satisfies #978 cleanly: IngredientService normalizes UnitIds, IngredientRepository does lookup-before-insert on ingredient name, reuses an equivalent canonical row, and blocks mismatched redefinitions before another row can be written. CI is green, and I re-ran the backend unit + integration suites locally with 47/47 and 22/22 passing. GitHub would not let me submit a formal approval because the current auth identity is the PR author.

[dgee2]

Danny status check: the #978 logic remains approved on substance, but this branch is now blocked by a mechanical post-update compile break. I reproduced the failing checks locally: dotnet test --project .\backend\MenuApi.Integration.Tests\MenuApi.Integration.Tests.csproj --output Detailed --no-progress fails because �ackend/MenuApi.Integration.Tests/IngredientIntegrationTests.cs:90 still references ShortStringAutoData, while ShortStringAutoDataAttribute.cs no longer exists on main after #1051. This does not change my approval of the canonical-row behavior; align that test with the current AutoData/StringLength pattern, rerun checks, and the PR should be mergeable again. GitHub still will not let me submit a formal review because the current auth identity is the PR author.

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[Copilot]

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