Expense Agent: capture submission policy evaluation history

Scope

Capture a report-level policy-evaluation snapshot for each expense report submission or resubmission. Checks on drafts/recalled reports must not create activity history.

Related planning: AB#634361 (activity history) and AB#626515 (policy evaluation). This issue does not replace or close either slice.

Companion service implementation: https://microsoft.ghe.com/bic/BC-ExpenseAgent/issues/2754

Expected behavior

• Reuse PolicyEvaluated with an explicit snapshot outcome, passed/failed line-policy counts, distinct flagged expense-line categories, and the latest underlying evaluation time.
• Capture complete current evidence during submission, or after the existing line confirmation checks that the entire pending-approval report is ready.
• Require submission history and enforce at most one snapshot since the latest Submitted/Resubmitted activity.
• Reuse the existing activity-log management codeunit. No new API actions, capability, callback, submission token, context hashing, or header-invalidation changes.
• Keep the activity API read-only and detailed policy-evaluation records intact.
• Preserve history through posting and keep existing API actions compatible.
• Respect the BC policy feature switch; never infer a clear result from missing evaluations.

Validation

Add AL unit/API coverage for both capture paths, repeated confirmation, resubmission, pending/non-pending states, incomplete/current evaluations, feature-off/no-policy behavior, category aggregation, and posting.
AL compilation, publication, runtime tests, and live cross-repository validation remain pending.

Start by locating the existing PolicyEvaluated activity record and activity-log management codeunit, then review the current submission, resubmission, and line-confirmation entry points. Add AL unit/API coverage for both capture paths and the listed edge cases; done means compilation, publication, runtime tests, and cross-repository validation pass without changing the read-only API or detailed evaluation records.