Add gat-description modal when a Pi-Rat earns a Gat

Mirrors the name modal: earning the Gat objective sets
Player.needs_gat_description, and GatModal.svelte (rendered by Dashboard
across all phases) prompts for a one-of-a-kind Gat description, stored in
Player.gat_description and shown on the character sheet. Like a stolen
Name, the Gat's description travels with it through Gat Tax transfers.

- Player.gat_description / needs_gat_description (+ migration)
- toggle_objective personal_1 sets/clears the prompt
- crud_challenge gat-tax paths move the description with the Gat
- set-gat-description route; CharacterSheet displays it

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

frontend/src/components/GatModal.svelte

@@ -0,0 +1,88 @@
+<script>
+    import { apiRequest } from '../lib/api';
+
+    export let state;
+
+    let descInput = '';
+    let error = '';
+    let submitting = false;
+
+    async function submitDescription() {
+        if (!descInput.trim() || submitting) return;
+        error = '';
+        submitting = true;
+        try {
+            await apiRequest(`/game/${state.game.id}/player/${state.player.id}/set-gat-description`, 'POST', {
+                description: descInput.trim()
+            });
+            descInput = '';
+        } catch (e) {
+            error = e.message;
+        } finally {
+            submitting = false;
+        }
+    }
+
+    function onKeydown(e) {
+        if (e.key === 'Enter') submitDescription();
+    }
+</script>
+
+{#if state.player.needs_gat_description}
+    <div class="modal-backdrop">
+        <div class="modal-box glass-panel">
+            <h3>🔫 You Got a Gat!</h3>
+            <p class="info-text">
+                Every Pi-Rat's Gat is one of a kind. What does yours look like?
+            </p>
+            {#if error}
+                <div class="alert alert-danger">{error}</div>
+            {/if}
+            <input
+                type="text"
+                bind:value={descInput}
+                class="input-field"
+                placeholder="e.g. A pearl-handled flintlock that smells of cheese"
+                on:keydown={onKeydown}
+                autofocus
+            >
+            <button
+                class="btn btn-gold btn-full"
+                on:click={submitDescription}
+                disabled={!descInput.trim() || submitting}
+            >
+                Claim Gat
+            </button>
+        </div>
+    </div>
+{/if}
+
+<style>
+    .modal-backdrop {
+        position: fixed;
+        inset: 0;
+        z-index: 2000;
+        display: flex;
+        align-items: center;
+        justify-content: center;
+        padding: 20px;
+        background: color-mix(in srgb, var(--bg-deep) 70%, transparent);
+        backdrop-filter: blur(6px);
+    }
+    .modal-box {
+        max-width: 440px;
+        width: 100%;
+        padding: 1.75rem;
+        border: 1px solid var(--edge);
+        border-radius: var(--radius-md);
+        box-shadow: var(--shadow-deep);
+        text-align: center;
+    }
+    .modal-box h3 {
+        margin-top: 0;
+    }
+    .modal-box .input-field {
+        width: 100%;
+        margin: 0.75rem 0;
+    }
+</style>

frontend/src/components/scene/CharacterSheet.svelte

@@ -80,6 +80,9 @@
             <p><strong>Look:</strong> {state.player.avatar_look}</p>
             <p><strong>Smell:</strong> {state.player.avatar_smell}</p>
             <p><strong>First Words:</strong> "{state.player.first_words}"</p>
+            {#if state.player.gat_description}
+                <p><strong>🔫 Gat:</strong> {state.player.gat_description}</p>
+            {/if}
         </div>
 
         {#if state.player.other_like || state.player.other_hate}