docs: update 5-4-manual-journal-entries.md

[habib424]

Drafted by Ship Ship 🚢 — confidence 🟢 high

What changed

Updated the "Workflow Approval for Entries" section to reflect the fully implemented journal-entry approval workflow: explained how to configure it in Settings → Workflows, described the UI changes (Post button becomes "Submit for approval" when a workflow is published), documented the "Pending approval" status badge and filter, and described the approval flow with Approve/Reject buttons and read-only form behavior during approval.

Source PRs

• axolotl#4473 — PLT-303: journal-entry approval gate (frontend)

How to use this PR

1. Review the diff against the existing article — focus on accuracy and customer voice.
2. Merge if it reads well. Edit and push to this branch if it needs adjustment.
3. Close without merging if the article doesn't actually need this update.

Once we have a track record of clean drafts, we'll graduate to auto-merge with a delay buffer. For now: human-in-the-loop.