fix: clinic creation gating, analysis line charts, username + task assignee, delete confirm

- Hide "Create clinic" (sidebar footer) for non-admins; only owner/admin can
  spin up additional clinics. Onboarding for brand-new users is unaffected.
- Analysis: drop the bar charts; show line charts (Sparkline) inside KPI cards
  that open a detail dialog with the full chart + per-point breakdown.
- Add Team Member: validate the username client-side (no spaces; letters,
  numbers, dots, underscores) with a clear warning + field hint.
- Tasks: New Task now has an Assignee selector (Myself / Other → department).
  Tasks are visible to the department they're assigned to (or the creator), and
  show who created them. Backend adds assignee_role + created_by_name with
  visibility filtering in listTasks; owners/admins see all.
- Care team: removing a member now asks for confirmation first (dialog) and
  surfaces success/failure + refreshes.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/drizzle/0008_luxuriant_blue_blade.sql

@@ -0,0 +1,2 @@
+ALTER TABLE "tasks" ADD COLUMN "assignee_role" text;--> statement-breakpoint
+ALTER TABLE "tasks" ADD COLUMN "created_by_name" text;

backend/drizzle/meta/_journal.json

@@ -57,6 +57,13 @@
       "when": 1780933857005,
       "tag": "0007_skinny_bloodstrike",
       "breakpoints": true
+    },
+    {
+      "idx": 8,
+      "version": "7",
+      "when": 1780937195597,
+      "tag": "0008_luxuriant_blue_blade",
+      "breakpoints": true
     }
   ]
 }