feat(pool): one board of pools with split/merge by drag; plan names from tier and seat

- The Users page account pool is one board: a column per pool holding its
  Claude Code, Codex and Cursor accounts (plan, quota, live panes) and its
  members. Accounts sit in one pool; drag moves them. Drop on New pool to
  split one off; drag a pool's only account into another pool to merge
  (members follow, the emptied pool is deleted on Save). One password Save.
- Claude plan label (planLabel in cc-profiles.js) reads rateLimitTier and
  seatTier: Max 5x/20x, Team Standard/Premium — subscriptionType alone said
  'pro' after an upgrade and 'team' for both seats. Shown on profiles, the
  status bar quota badge and pool cards; Codex pool cards show the ChatGPT plan.

docs/SERVER-MODE.md

@@ -595,7 +595,7 @@ agenthub accounts pin cursor-team mia --tool cursor
 ## Account pool groups
 
 By default every user shares every pool account. **Groups** split the pool
-by team (Users page → **Account pool → Groups**, server mode only,
+by team (Users page → **Account pool**, where a group is called a pool, server mode only,
 `server/lib/pool-groups.js`):
 
 - A group has a name, members and accounts of every pool tool (Claude, Codex,
@@ -613,6 +613,28 @@ by team (Users page → **Account pool → Groups**, server mode only,
   an account takes it out of every group; deleting a group sends its members
   back to the shared pool and removes no account.
 
+On the Users page a group is shown as a **pool**: the **Account pool** card
+is one board with a column for the shared pool and one per pool, each
+holding its accounts of every tool (grouped by tool, each a card with its
+plan — "Max 5x", "Team Premium", a ChatGPT plan —, live panes and quota) and
+its members. Drag an account or a member from one
+column to another — in the UI an account sits in ONE pool, so a drop moves
+it (onto the shared pool takes it off every pool). Dropping one on the
+trailing **New pool** column SPLITS it off into a new pool of its own;
+dragging a pool's ONLY account into another column MERGES that pool there —
+its members come along and the emptied pool is deleted on save. A column's **+ Move an
+account or saved profile here** menu does the same without dragging and also
+lists the saved login profiles, which are moved into the pool on save; **Pick
+members** ticks members by role (Admin / Developer / Analyst) or **No pool**
+in a dialog; **Add account** in the card's header adds a new account for a
+chosen tool (it lands in the shared pool). Nothing is sent until **Save**,
+which asks for the password once and applies every change (profiles moved
+in, then new pools created, then each changed pool set exactly, then merged
+pools deleted); a failed
+step keeps the board so a retry resumes where it stopped. Tools with no pool
+(Oh My Pi, any other installed tool) keep a tab each under **Other AI
+tools**. An account's Edit (pencil) uses the same role / No pool list.
+
 ### A user's own pool account
 
 When the pool holds more than one account a user may use, they pick which one