feat(berths): active-interests popover + row-density toggle on berth list

Two complementary UX upgrades on the berth list:

1. Active-interests popover — replaces the plain "Active interests"
   count cell with a click-to-expand popover. Each row shows the
   linked deal's client name, pipeline stage (with stage-badge tint),
   and a primary-star icon. Lazy-loads on first open (30s stale),
   capped at 20 entries server-side, sorted most-recently-updated
   first. Backed by `GET /api/v1/berths/[id]/active-interests`.

2. Row-density toggle — DataTable gains a `density: 'comfortable' |
   'compact'` prop. Compact drops cell vertical padding from py-3 to
   py-1.5 so reps can scan many more berths per viewport on the
   high-density admin lists.

   Persisted alongside hidden-columns in `user_profiles.preferences.
   tablePreferences[entityType].density`. Hook returns `density +
   setDensity`; defaults to 'comfortable' for users who haven't
   chosen. The setter shares the same debounced PATCH with setHidden
   so toggling both doesn't multiply the network round-trips.

   Toolbar adds a Rows3/Rows4 icon button between the saved-views
   dropdown and the ColumnPicker. tooltip + aria-label flip to
   communicate the next state.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/lib/db/schema/users.ts

@@ -174,6 +174,10 @@ export type RolePermissions = {
  */
 export type TablePreferences = {
   hiddenColumns?: string[];
+  /** Row density. Absent = comfortable (the default; matches shadcn's
+   *  default cell padding). 'compact' drops vertical padding so reps
+   *  can scan more rows per viewport. */
+  density?: 'comfortable' | 'compact';
 };
 
 export type UserPreferences = {