Story: Create a user guide for ores.qt

Build out the user guide for the Qt application chapter by chapter. The manual's delivery infrastructure (PDF build, book class, site publishing) landed in sprint 18; the content chapters started this sprint with provisioning (chapter 3), reference data (chapter 4) and currencies (chapter 5). This story is the single home for manual-content work going forward — previously such tasks were scattered across commissioning and documentation stories, which made the manual's progress invisible.

Next up: an administration chapter covering the day-to-day IAM windows — accounts (list, details with parties/roles/security tabs, new-account flow), roles, and tenants — using the screenshot set captured on 2026-06-04 (assets/images/account_*, roles_*, tenants_*).

• The user guide gains an administration chapter documenting the accounts, roles and tenants Qt windows, illustrated with the existing screenshots, following the established chapter conventions.
• Cross-cutting UI behaviour (paging, badges, provenance, change reasons) is described once and referenced, consistent with the UX Language doc.
• The product identity document links to the user manual.
• user_manual.pdf rebuilt; site builds cleanly.

• Manual-content tasks live here from now on; commissioning stories link to (rather than own) their documentation tasks.
• The in-flight Write currency documentation task stays in Commission: currency for now — it is STARTED on feature/currency-write-docs in another worktree and moving the file would conflict; it (or its successors) migrate here once that PR lands.

• Shell documentation per chapter — tracked by Entity manual: shell documentation.
• Manual delivery infrastructure (done in sprint 18).