V1.1.0: gear levels, encounter overhaul, guided builder, trading, docs

Characters
- Builder: pick-then-Next on every step with live preview, Back button,
  plain-language help throughout, and "Suggest for me" for ability scores
- Motivation is picked from a list; new steps for special abilities,
  background and appearance, all composed from fixed lists and DM-only
  to edit afterwards
- Copy a character to another campaign
- Characters can give gold, weapons, items and spells to each other
- Money tracker: gold only changes through a logged ledger
- Fixes: level/XP/location are DM-only, HP stays within 0..max, physical
  dice ability rolls, every die is rolled once

Gear
- DM-managed item pool; weapons, items and spells are handed out by the DM
- Starting-option flag per pool entry
- Gear levels 1-9 per held copy with a damage ladder, growth rate and
  starting level; spells gated by spell level with a fixed damage value
- Spell library carries default damage; damage is picked from a list

Encounters
- Battle and NPC quest modes, turn tracking, scene description, DM notes
- NPCs, richer combatant cards, conditions from a list
- Rewards (gold, weapons, items) lined up and awarded, with gold splitting
- Character HP is shared between the sheet and the encounter
- Monster stat blocks and NPC secrets are never sent to players

Other
- Dice roller on every page
- Docs for characters, weapons, spells, items, encounters, monsters and
  NPCs, with full lists generated from the data (npm run docs:lists)

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

docs/ITEMS.md

@@ -0,0 +1,151 @@
+# Items and Inventory
+
+How items work in this app: the campaign's item pool, what a character
+carries, item levels, and how items are handed out.
+
+This describes the code as it stands. Related: [WEAPONS.md](WEAPONS.md) (items
+level up the same way weapons do), [SPELLS.md](SPELLS.md),
+[CHARACTERS.md](CHARACTERS.md) (money is covered there, in section 12).
+
+## Contents
+
+1. [The basics](#1-the-basics)
+2. [The item pool](#2-the-item-pool)
+3. [A character's inventory](#3-a-characters-inventory)
+4. [Item levels](#4-item-levels)
+5. [Dice on items](#5-dice-on-items)
+6. [Starting items](#6-starting-items)
+7. [Items as rewards](#7-items-as-rewards)
+8. [Permissions](#8-permissions)
+9. [What is not modelled](#9-what-is-not-modelled)
+
+---
+
+## 1. The basics
+
+- Every campaign has its own **item pool**: rope, potions, keys, quest items,
+  anything that is not a weapon or a spell.
+- A character's **inventory** is the items it holds from that pool. Players
+  cannot type in items of their own.
+- The DM creates items and hands them out. Players can only tick Equipped.
+- Items are **descriptive**. Holding or equipping one never changes a number
+  on the sheet.
+
+## 2. The item pool
+
+The pool is the "Items Pool" card on the campaign page (DM only).
+
+| Field | What it is |
+|---|---|
+| Name | Free text, up to 120 characters |
+| Description | Optional. Shown under the item in a character's inventory |
+| Base dice | Optional dice such as `2d4+2`, for items that deal damage or heal (section 5) |
+| Starts at level | 1 to 9. The lowest level this item can be (section 4) |
+| Growth | Standard, Powerful or Legendary. Only matters if the item has dice |
+| Starting option | Whether a brand-new character may pick it in the builder (section 6) |
+
+- **Adding:** the "+ Add Item" form. There is no built-in library of items.
+- **Changing:** starting level, growth (when the item has dice) and the
+  starting-option tick box can be changed in the table. Name, description and
+  dice cannot be changed on screen once created (the API accepts it); remove
+  and re-add instead.
+- **Removing:** the ✕ button. This takes the item out of **every inventory**
+  and off every encounter's reward list. There is no undo.
+
+## 3. A character's inventory
+
+On a character's sheet, the DM picks an item from the pool and clicks Give.
+
+| Each held item has | Who changes it |
+|---|---|
+| Quantity | The DM, with the − and + buttons |
+| Level | The DM, with the level picker |
+| Equipped | The owning player or the DM |
+
+- Giving an item the character already holds **adds to the stack**. A
+  character holds one stack per item, and the whole stack shares one level.
+- Quantity cannot go below 1; to take the last one away the DM uses ✕.
+- **Using up** an item (drinking a potion) is not automatic: the DM lowers the
+  quantity or removes it.
+- **Equipped** is a label. It does not change Armor Class or anything else;
+  armor is represented by the single "armor bonus" number on the sheet.
+
+**Passing items on.** A character's owner (or the DM) can give some or all of
+a held stack to another character in the campaign from the "Give to Another
+Character" card on the sheet. The items leave the giver and arrive with the
+recipient at the giver's level, unequipped. If the recipient already holds
+that item, their stack grows and keeps its own level. Gold is given the same
+way, and both characters' money logs record it.
+
+## 4. Item levels
+
+Items use the same level system as weapons (a house rule of this app):
+
+- Each held stack has a **level from 1 to 9**, never below the pool entry's
+  starting level.
+- A character must be **at least the item's level** to use it. A higher-level
+  item is still held, but shows "Requires level N" and cannot be equipped.
+- Only the DM changes an item's level.
+- If the DM levels an item past its holder, or lowers the character's level,
+  it is unequipped automatically.
+
+For an item with no dice, the level is purely a requirement: a level 3 amulet
+is one a character cannot use until level 3.
+
+## 5. Dice on items
+
+An item can carry optional dice: a healing potion's `2d4+2`, a firebomb's
+`3d6`. The app does not know whether they heal or harm; the DM applies them.
+
+The dice grow with the item's level exactly as a weapon's do, climbing the
+same ladder (1d4 → 1d6 → 1d8 → 1d10 → 1d12 → 2d6 → …) by one, two or three
+rungs per level depending on Growth. The full ladder is in
+[WEAPONS.md, section 6](WEAPONS.md#6-how-damage-grows).
+
+| Healing Potion, `2d4+2`, Standard growth | Dice shown |
+|---|---|
+| Level 1 | 2d4+2 (as typed) |
+| Level 2 | 1d6+1d8 |
+| Level 3 | 2d8 |
+
+The dice are shown beside the item in the inventory. Nothing is rolled or
+applied automatically; use the dice roller.
+
+## 6. Starting items
+
+In the builder's equipment step a new character can pick items that are:
+
+- ticked as a **starting option** in the pool, and
+- **starting level 1**.
+
+Starting items and starting weapons share the campaign's "starting items"
+allowance. Each arrives at level 1, quantity 1, unequipped.
+
+## 7. Items as rewards
+
+On an encounter the DM can line up an item as a reward, at a chosen level and
+quantity, and later award it to a character. Awarding adds it to the
+character's inventory, stacking with any they already hold. See
+[ENCOUNTERS.md](ENCOUNTERS.md).
+
+## 8. Permissions
+
+| Action | DM | Owning player | Other players |
+|---|---|---|---|
+| See the item pool | Yes | Yes | Yes |
+| 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 |
+| Change quantity or level | Yes | No | No |
+| Equip or unequip | Yes | Yes, if the character can use it | No |
+| See a character's inventory | Yes | Yes | Yes |
+
+## 9. What is not modelled
+
+- Any effect of an item on stats (AC, speed, abilities)
+- Armor and shields as items
+- Using up items automatically, charges, and attunement
+- Weight, carrying capacity and containers
+- Prices, buying and selling (record the gold change in the money log)
+- Swaps as a single step (each side gives separately), and asking the
+  recipient to accept