fix(teams): answer a duplicate team name with 409

[GoddeyUwamari]

Summary

POST /api/teams returned 500 when the requested team name was already taken. It now returns 409 with a fixed message:

{ "success": false, "error": "A team with this name already exists.", "message": "A team with this name already exists." }

Only the unique violation on the team name is mapped. Every other database error keeps the existing 500 response.

Changes

• backend/src/controllers/teams.controller.ts: map the team-name unique violation to 409 in create.
• backend/src/routes/__tests__/teams-duplicate-name.test.ts: new route tests against Postgres.

There is no team update route, so there is no rename path to handle.

Not changed

• No schema change and no migration.
• No change to authentication, authorization, or scoping.
• No frontend change.

Tests

• Duplicate name → 409 with exactly the body above; the existing team is untouched and no second row is written.
• Successful create → 201, unchanged.
• Unrelated database error → 500, unchanged.
• Unique violation on a different constraint → 500, unchanged.
• Missing required fields → 400, unchanged.

Run locally against a database built with .github/scripts/ci-bootstrap-schema.js: the new file passes 5/5, and the duplicate-name test fails without the controller change. Backend tsc --noEmit is clean.

🤖 Generated with Claude Code

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Project	Deployment	Actions	Updated
devcontrol	Ready	Preview	Oct 5, 2026 7:00am UTC