Add activity lifecycle E2E test fixture

[Prangshuman Das (t-prda)]

Summary

Add deterministic Business Central setup for the Expense Agent activity lifecycle E2E tests.

• Add ExpenseTestHandler_ConfigureApprovalScenario.
• Configure a distinct approver Expense User for the current BC service account.
• Create or replace the submitter-to-approver Expense Approval Setup.
• Keep the standard BC approval workflow disabled so the tests exercise Expense Agent service approval routing without a User Setup dependency.
• Reject using the same Expense User as both submitter and approver.

This is the BCApps companion to BC-ExpenseAgent PR #2391.

Tracking

• AB#646914

Validation

• git diff --check
• Test app compiled and published manually.
• Live BC lifecycle E2E: submit/approve passed.
• Live BC lifecycle E2E: reject/resubmit/reapprove passed.

[Prangshuman Das (t-prda)]

Agentic PR Review - Round 1

Recommendation: Request Changes

What this PR does

This PR adds a test-handler endpoint that prepares two Expense Users for externally run approval lifecycle tests. It maps the approver to the current BC service identity, replaces the submitter's approval setup, and disables the standard BC approval workflow.

The setup path is otherwise narrow and matches the external test goal. However, assigning the service identity does not make that identity unique, while the approval code resolves it with FindFirst().

Suggestions

S1 - Make the approver identity deterministic
Clear UserId() from other Expense Users before assigning it here. Initialize() keeps Expense Users, and approval lookup uses FindFirst() on this non-unique field. A stale lower-key user can be selected on a later external test run.

Risk assessment and necessity

Risk: The changed code is test-only and does not affect the production app. The current identity setup can still make external lifecycle tests use the wrong Expense User, which gives unstable results and incorrect activity actors after a stale or interrupted run.

Necessity: A deterministic setup endpoint is needed for the linked lifecycle E2E coverage. The scope is appropriate once the service identity is made unique for each fixture run.

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[AI-PR-REVIEW] version=1 promptVersion=1 system=github pr=10365 round=1 by=t-prda at=2026-08-18T15:19:12.3771320Z lastSha=4663a795121aa4987f3bff1a0a2359b0d81c9107 reviewKey=158c59f430abca4178e951bc8dba8675912e8702448d165cbd18bf5f9840e32d suggestions=S1@7eedcc06

[Prangshuman Das (t-prda)]

Addressed S1 in 7c4f7a8. The fixture now clears the current service UserId() from every existing Expense User before assigning it to the dedicated approver, so FindFirst() cannot select a stale lower-key user on subsequent runs.