Expense Agent: capture submission policy evaluation history

[Prangshuman Das (t-prda)]

Summary

Capture at most one report-level PolicyEvaluated history snapshot for each submission/resubmission using two existing BC execution paths.

• Store outcome, passed/failed line-policy counts, and distinct flagged category display names (description with code fallback).
• Use the history event time only; no snapshot-present flag, separate evaluation timestamp, or category-count field.
• Share a bounded JSON-array helper with the existing Categories snapshot; append a separate final "..." entry on overflow while continuing to count all policy checks.
• After submission/resubmission, log if all report lines have complete, current evaluations.
• After the existing MarkPoliciesEvaluated line confirmation, use the same helper to check the whole pending-approval report and log when ready.
• Require submission history and deduplicate against the latest Submitted/Resubmitted entry using existing log ordering.
• Keep draft/recalled manual checks unlogged. A check completing for a pending report follows the same state-based rule regardless of its trigger.
• Preserve detailed evaluations, approval behavior, history permissions, and posting behavior.
• Keep the helper in Expense Activity Log Mgt. with header-first report-scoped locking.

Simplification

Removed the separate Expense Policy History codeunit, new submit/completion API actions, capability, correlation fields, context hashes, and header-invalidation subscribers. No service callback is required. Only the existing read-only activity API gains snapshot fields.

Tracking

Closes #11627

Related planning: AB#634361 and AB#626515 (neither slice is closed by this PR).
Companion service issue: https://microsoft.ghe.com/bic/BC-ExpenseAgent/issues/2754

Companion draft PR: https://microsoft.ghe.com/bic/BC-ExpenseAgent/pull/2755

Validation and review

• Static AL structure/field checks and git diff --check.
• Consolidated 20 added regression tests in codeunits 148342 and 148343, retaining aggregation, name deduplication/overflow, completion, lifecycle, posting-reassignment, and API coverage.
• AL compile/publish/runtime tests: intentionally deferred to manual validation.
• Existing API, permissions, and concurrent-capture verification.
• End-to-end validation with the companion service change.

Draft for code review. No dispatch or AL execution was performed.
The initial implementation targets main; the planned 29.0 backport is not included.