V1.6.0: targets and an attack bar in encounters

- One combatant at a time can be marked as the target with the Target
  button on its card. The DM can mark anyone at any time; a player can
  while their own character is on turn in a battle.
- The target's card is outlined for everyone and names who is going for it.
- While a target is marked the DM gets an attack bar above the list: who is
  attacking whom, the target's AC and HP, the attacker's weapons, spells or
  monster attack, and a box to apply damage or healing straight away.
- The target is cleared when the turn or round moves on, when the encounter
  begins, ends or is reopened, or when the target is removed.
- All packages at version 1.6.0.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

package-lock.json

@@ -1,19 +1,19 @@
 {
   "name": "dnd-campaign-manager",
-  "version": "1.5.0",
+  "version": "1.6.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "dnd-campaign-manager",
-      "version": "1.5.0",
+      "version": "1.6.0",
       "workspaces": [
         "backend",
         "frontend"
       ]
     },
     "backend": {
-      "version": "1.5.0",
+      "version": "1.6.0",
       "dependencies": {
         "@prisma/client": "^5.20.0",
         "bcrypt": "^5.1.1",
@@ -31,7 +31,7 @@
       }
     },
     "frontend": {
-      "version": "1.5.0",
+      "version": "1.6.0",
       "dependencies": {
         "@tanstack/react-query": "^5.103.2",
         "axios": "^1.20.0",