feat: Trail-Liste mit Vorschaukarten

Übersichtsseite zeigt alle Trails des Teams als Grid mit Kartvorschau,
Status-Badge und Kennzahlen. Dialog für Trail-Erstellung mit GPX-Upload
im nächsten Schritt.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

frontend/src/routes/dashboard/trails/+page.svelte

@@ -0,0 +1,190 @@
+<script lang="ts">
+    import { goto } from '$app/navigation'
+    import { getTrailContext } from '$lib/stores/trails.svelte'
+    import { getTrailVersionContext } from '$lib/stores/trailVersions.svelte'
+    import { getTrailMarkerContext } from '$lib/stores/trailMarkers.svelte'
+    import TrailMap from '$lib/components/TrailMap.svelte'
+    import { Button } from '@/components/ui/button'
+    import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card'
+    import { Badge } from '@/components/ui/badge'
+    import { Input } from '@/components/ui/input'
+    import { Label } from '@/components/ui/label'
+    import * as Dialog from '@/components/ui/dialog'
+    import { Plus, Route, AlertTriangle } from 'lucide-svelte'
+    import type { TrailVersionsResponse } from '$lib/types'
+
+    const trails = getTrailContext()
+    const versions = getTrailVersionContext()
+    const markers = getTrailMarkerContext()
+
+    let dialog = $state(false)
+    let form = $state({ name: '', description: '' })
+    let saving = $state(false)
+    let error = $state<string | null>(null)
+
+    const STATUS_LABEL = {
+        offen: 'Offen',
+        eingeschraenkt: 'Eingeschränkt',
+        gesperrt: 'Gesperrt',
+    } as const
+
+    const STATUS_VARIANT = {
+        offen: 'default',
+        eingeschraenkt: 'secondary',
+        gesperrt: 'destructive',
+    } as const
+
+    type LineGeoJSON = { type: 'LineString'; coordinates: [number, number][] }
+
+    /** Aktive Version eines Trails, für Kennzahlen und Kartenlinie */
+    function currentVersion(trailId: string): TrailVersionsResponse<
+        [[number, number], [number, number]] | null,
+        unknown,
+        LineGeoJSON | null
+    > | null {
+        const trail = trails.getById(trailId)
+        if (!trail?.current) return null
+        return (versions.records.find((v) => v.id === trail.current) ?? null) as TrailVersionsResponse<
+            [[number, number], [number, number]] | null,
+            unknown,
+            LineGeoJSON | null
+        > | null
+    }
+
+    function formatKm(m: number | undefined) {
+        if (!m) return '–'
+        return `${(m / 1000).toFixed(1)} km`
+    }
+
+    async function save() {
+        if (!form.name.trim()) {
+            error = 'Bitte einen Namen angeben.'
+            return
+        }
+
+        saving = true
+        error = null
+        try {
+            const rec = await trails.create({
+                name: form.name.trim(),
+                description: form.description,
+            })
+            dialog = false
+            form = { name: '', description: '' }
+            await goto(`/dashboard/trails/${rec.id}`)
+        } catch (e: any) {
+            error = e.message ?? 'Der Trail konnte nicht angelegt werden.'
+        } finally {
+            saving = false
+        }
+    }
+</script>
+
+<div class="space-y-6">
+    <div class="flex items-center justify-between">
+        <div>
+            <h1 class="text-2xl font-semibold">Trails</h1>
+            <p class="text-muted-foreground text-sm">
+                {trails.scoped.length}
+                {trails.scoped.length === 1 ? 'Trail' : 'Trails'} im Team
+            </p>
+        </div>
+        <Button onclick={() => (dialog = true)}>
+            <Plus class="size-4 mr-2" />
+            Neuer Trail
+        </Button>
+    </div>
+
+    {#if trails.loading}
+        <p class="text-muted-foreground">Trails werden geladen …</p>
+    {:else if trails.scoped.length === 0}
+        <Card>
+            <CardContent class="py-10 text-center space-y-3">
+                <Route class="size-10 mx-auto text-muted-foreground" />
+                <p class="text-muted-foreground">
+                    Noch kein Trail angelegt. Leg einen an und lade eine GPX-Datei hoch.
+                </p>
+                <Button onclick={() => (dialog = true)}>
+                    <Plus class="size-4 mr-2" />
+                    Neuer Trail
+                </Button>
+            </CardContent>
+        </Card>
+    {:else}
+        <div class="grid gap-4 md:grid-cols-2 lg:grid-cols-3">
+            {#each trails.scoped as trail (trail.id)}
+                {@const version = currentVersion(trail.id)}
+                {@const open = markers.openByTrail(trail.id).length}
+                <a href="/dashboard/trails/{trail.id}" class="block">
+                    <Card class="h-full hover:border-primary transition-colors">
+                        <CardHeader class="pb-3">
+                            <div class="flex items-start justify-between gap-2">
+                                <CardTitle class="text-base">{trail.name}</CardTitle>
+                                <Badge variant={STATUS_VARIANT[trail.status] ?? 'default'}>
+                                    {STATUS_LABEL[trail.status] ?? trail.status}
+                                </Badge>
+                            </div>
+                        </CardHeader>
+                        <CardContent class="space-y-3">
+                            {#if version?.geojson}
+                                <TrailMap
+                                    geojson={version.geojson}
+                                    bounds={version.bounds}
+                                    status={trail.status}
+                                    height="140px"
+                                />
+                            {:else}
+                                <div class="h-[140px] rounded-lg border border-dashed grid place-items-center text-sm text-muted-foreground">
+                                    Noch keine GPX-Datei
+                                </div>
+                            {/if}
+
+                            <div class="flex items-center gap-4 text-sm text-muted-foreground">
+                                <span>{formatKm(version?.distance_m)}</span>
+                                <span>{version?.ascent_m ? `${version.ascent_m} hm` : '–'}</span>
+                                {#if open > 0}
+                                    <span class="flex items-center gap-1 text-amber-600 ml-auto">
+                                        <AlertTriangle class="size-4" />
+                                        {open}
+                                    </span>
+                                {/if}
+                            </div>
+                        </CardContent>
+                    </Card>
+                </a>
+            {/each}
+        </div>
+    {/if}
+</div>
+
+<Dialog.Root bind:open={dialog}>
+    <Dialog.Content>
+        <Dialog.Header>
+            <Dialog.Title>Neuer Trail</Dialog.Title>
+            <Dialog.Description>
+                Die GPX-Datei lädst du im nächsten Schritt hoch.
+            </Dialog.Description>
+        </Dialog.Header>
+
+        <div class="space-y-4">
+            <div class="space-y-2">
+                <Label for="trail-name">Name</Label>
+                <Input id="trail-name" bind:value={form.name} placeholder="z. B. Steinberg-Abfahrt" />
+            </div>
+            <div class="space-y-2">
+                <Label for="trail-desc">Beschreibung</Label>
+                <Input id="trail-desc" bind:value={form.description} placeholder="optional" />
+            </div>
+            {#if error}
+                <p class="text-sm text-destructive">{error}</p>
+            {/if}
+        </div>
+
+        <Dialog.Footer>
+            <Button variant="outline" onclick={() => (dialog = false)}>Abbrechen</Button>
+            <Button onclick={save} disabled={saving}>
+                {saving ? 'Wird angelegt …' : 'Anlegen'}
+            </Button>
+        </Dialog.Footer>
+    </Dialog.Content>
+</Dialog.Root>