feat(uat-batch): Group N — dashboard upgrades

N44, N45, N46 from the 2026-05-21 plan.

Shipped:
  N44  Pipeline Value tile respects dashboard timeframe. Tile accepts
       optional `range` prop and threads it through
       /api/v1/dashboard/kpis?range=<slug> + /forecast?range=<slug>.
       Service functions accept optional {from,to} bounds and scope
       the pipeline-value SQL to interests created within the window.
       New parseRangeSlug helper inverts rangeToSlug. Widget registry
       forwards the active dashboard range to the tile.
  N45  Clients by country widget. New GET
       /api/v1/dashboard/clients-by-country groups non-archived
       clients by nationality_iso. <ClientsByCountryWidget> renders a
       compact ranked list with mini-bars; rows link to
       /clients?nationality=<ISO>. Registered as default-visible rail.
  N46  Drag-and-drop dashboard widgets. New
       preferences.dashboardWidgetOrder?: string[] on user_profiles;
       useDashboardWidgets sorts visibleWidgets by the order
       (unlisted ids fall through to registry order) and exposes
       setOrder(nextOrder) that PATCHes optimistically.
       DashboardShell wires @dnd-kit/core + sortable: Rearrange toggle
       turns on per-widget grip handles + sortable-context wraps each
       group (charts / rails / feed) so drops stay in-group.
       PointerSensor 8px activation distance, KeyboardSensor for a11y.
       New <SortableWidget> wraps the render — zero footprint when
       off.

Verified: tsc clean, vitest 1454/1454.

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

src/lib/analytics/range.ts

@@ -45,6 +45,20 @@ export function rangeToSlug(range: DateRange): string {
   return range;
 }
 
+/**
+ * Inverse of rangeToSlug — parses a `?range=<slug>` query-string value
+ * back into a typed DateRange. Returns null on garbage input so callers
+ * can fall through to their "no range" default rather than 400ing.
+ */
+export function parseRangeSlug(slug: string): DateRange | null {
+  if (ALL_RANGES.includes(slug as PresetDateRange)) return slug as PresetDateRange;
+  // Custom: `YYYY-MM-DD_YYYY-MM-DD`. Both halves must look like ISO dates;
+  // anything else is malformed.
+  const m = /^(\d{4}-\d{2}-\d{2})_(\d{4}-\d{2}-\d{2})$/.exec(slug);
+  if (!m) return null;
+  return { kind: 'custom', from: m[1]!, to: m[2]! };
+}
+
 /**
  * Resolve any DateRange (preset or custom) to a concrete {from, to} pair.
  * - Preset ranges anchor `to` at "now" and `from` at `now - N days`.