Extract Vue frontend into separate container and add stp_wasm crate

Move Vue app from nginx/vue/ to top-level vue/ with its own Dockerfile,
update docker-compose configs and nginx proxy to serve from the new
container, and add initial Rust WASM crate (stp_wasm). Also fix .gitignore
to exclude Rust target/ directories.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

vue/src/views/admin/CreateRowing.vue

@@ -0,0 +1,51 @@
+<script setup>
+import Button from "@/components/input/Button.vue";
+import { ref } from "vue";
+import axios from "axios";
+
+const images = ref([]);
+const results = ref([]);
+
+function onFileChange(e) {
+    images.value = Array.from(e.target.files);
+    results.value = [];
+}
+
+async function submit() {
+    if (!images.value.length) return;
+    results.value = images.value.map((f) => ({ name: f.name, status: "Uploading..." }));
+
+    await Promise.all(
+        images.value.map(async (file, i) => {
+            const formData = new FormData();
+            formData.append("image", file);
+            try {
+                const res = await axios.post("/api/rowing", formData, {
+                    headers: { "Content-Type": "multipart/form-data" },
+                });
+                const mins = Math.floor(res.data.Time / 1e9 / 60);
+                const secs = String(Math.floor((res.data.Time / 1e9) % 60)).padStart(2, "0");
+                results.value[i].status = `${res.data.Distance}m in ${mins}:${secs}`;
+                results.value[i].ok = true;
+            } catch (err) {
+                results.value[i].status = err.response?.data?.error || "Upload failed";
+                results.value[i].ok = false;
+            }
+        })
+    );
+
+    images.value = [];
+}
+</script>
+
+<template>
+    <div class="flex flex-col gap-2">
+        <h1>Create Rowing</h1>
+        <input type="file" accept="image/jpeg,image/png,image/gif,image/webp" multiple @change="onFileChange" />
+        <Button @click="submit">Upload</Button>
+        <div v-for="r in results" :key="r.name">
+            <span class="text-primary">{{ r.name }}: </span>
+            <span :class="r.ok ? 'text-secondary' : 'text-red-500'">{{ r.status }}</span>
+        </div>
+    </div>
+</template>