Task: Write accounts, roles and tenants administration chapter

Add an administration chapter to the user guide covering the day-to-day IAM windows in ores.qt:

• Accounts — list window (as system admin and tenant admin), detail dialog with its Parties, Roles and security tabs, login status badges, the new-account flow (including password reveal and party/role assignment), eventing, and the missing-party state.
• Roles — list window and detail dialog (general, permissions, provenance).
• Tenants — list window with status badges and detail dialog (general, provenance).

The screenshot set captured on 2026-06-04 covers all of these (assets/images/account_*, roles_*, tenants_*). Follow the established chapter conventions (see chapters 3-5) and the UX Language doc for the shared vocabulary (badges, paging, provenance); describe cross-cutting behaviour by reference, not by repetition. Use the Manual Updater skill for the mechanics (chapter wiring, PDF rebuild).

• New chapter in doc/manual/user_guide/ wired into user_manual.org, covering accounts, roles and tenants windows with at least one screenshot per window.
• Login identity context is explicit (system admin vs tenant admin views differ; see the two accounts list screenshots).
• Cross-cutting behaviour (paging, badges, provenance, change reasons) referenced once, not repeated per entity.
• user_manual.pdf rebuilt; site builds cleanly.

(Transient implementation strategy. Written when work starts; distilled into the parent story's * Decisions and cleared when the task closes. Plans do not outlive their task.)

Delivered in PR #1063. Added the Administration part with two new chapters. Accounts and Roles: the Accounts window as platform versus tenant administrator, live updates, the six-tab detail dialog, the complete new-account flow (including the no-roles warning note), and the RBAC treatment — account/permission/role trio, service roles, and the full domain-role table sourced from the seed data. Tenants: now the canonical home of the multi-tenant, multi-party model (moved from Initial Setup, which keeps a primer), the type taxonomy, the window with lifecycle badges, and the detail dialog. Nineteen screenshots placed; PDF rebuilt throughout.

The chapter work drove a manual-wide quality pass: thesis-style lettrine abstracts on every chapter with varied openers and Summary closings (Introduction exempt); uniform abstract-heading-content shape; float tuning to eliminate image-only pages; prose interleaved between all figure runs; the domain-roles table split to fit the text column and captioned; heading spacing restored after diagnosing lettrine swallowing titlesec's beforeskip; dead intra-manual chapter links fixed via CUSTOM_ID labels; external org-roam links now export as site URLs in the PDF; subscript interpretation disabled.