V1.3.0: Hollowcrown seed, player visibility rules, initiative rolls, number limits, temp HP

- Hollowcrown: The Rift Between Worlds as its own seed (npm run
  seed:hollowcrown), built from the campaign book: pools, 58 monsters,
  57 NPCs, 28 locations, 72 encounters with rewards, and DM notes. Shared
  seeding logic moved to prisma/seedCampaign.js.
- What players can see: only encounters their own character is in; only
  the pool entries their character holds (plus starting options while
  building); only locations their character has been to; no invite code;
  no gold, inventory or money log of other players' characters. Socket
  events carry ids only and campaign rooms are members-only.
- Encounters have a location; while one is in progress its characters are
  there, and visits are remembered.
- Campaign setting to show players a health bar only for monsters and NPCs.
- Initiative is entered as the d20 roll (1-20) and the bonus is added;
  players can enter their own character's roll.
- Number fields enforce their limits when typing, and the API enforces
  the same limits.
- Temp HP shows on HP bars and absorbs damage before real HP.
- All packages at version 1.3.0.

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

docs/ITEMS.md

@@ -132,7 +132,7 @@ character's inventory, stacking with any they already hold. See
 
 | Action | DM | Owning player | Other players |
 |---|---|---|---|
-| See the item pool | Yes | Yes | Yes |
+| See the item pool | Yes | Only what their own character holds, plus the starting options while they have a character to build | The same, for their own character |
 | Add, change or remove pool items | Yes | No | No |
 | Give an item from the pool, or take one away | Yes | No | No |
 | Give a held item to another character | Yes | Yes | No |