Board Category Customization, Smarter Renumbering, and a Clearer Model Picker

Customize categories directly on the board: rename, recolor, and reorder categories from the new Categories panel (Display menu) or by right-clicking a category header — changes apply instantly across headers, cards, and the panel for everyone on the engagement.
Drag rows into a custom order: dragging a request or task within its group now places it exactly where you drop it, automatically switching that view to Manual ordering (with an Undo toast if you change your mind).
Set default view for everyone: auditors can publish their current board arrangement — layout, grouping, sorting, and filters — as the shared default for the whole engagement team and for clients.
Renumber now works under any sort order, in both Board and List views (previously it only worked when sorted by Manual or Identifier). Repeated renumbering also keeps same-named items in a stable order instead of shuffling them.

The model picker pill now always names the AI model that will actually respond (e.g. "GPT-6.1 Sol · Medium") instead of an ambiguous "Default." It opens into a streamlined panel with an effort slider, a one-click jump to the fastest setting, and a reset to the recommended model and effort.
Rename an open chat directly from its options menu in task chat, in addition to renaming from the chat history list.
"Manage skills" and "Add skill" are back in the composer's "+" menu.
Large AI-built spreadsheets and multi-tab workbooks are far less likely to be rejected for size — the AI also now knows to build large datasets in steps when needed.

Client and engagement creation now use a streamlined flow with clearer empty states, and engagement settings (members, categories, roll-forward, reference documents) are reorganized into clearer sections.
Removed a redundant "Settings" option from the engagement view's own menu, since that view already is the engagement's settings.

A subrequest's title now updates immediately everywhere it's shown after a rename, instead of requiring a page reload.