Restructure Web App into server/ + web/ (GsmNode parity)

Reorganize the Web App to match the GsmNode project layout: a Go
backend-for-frontend in server/ that embeds the built SPA and reverse-proxies
/api/* to the API Server, with the Vue 3 + Vite frontend moved into web/.

- Move all frontend files into web/ (history preserved via renames)
- Point vite build output at ../server/dist for Go embedding
- Add server/ Go BFF (main.go, go.mod, .env.example, Run-WebApp.ps1)
- Drop Docker/nginx deploy (Dockerfile, docker-compose.yml, nginx.conf.template,
  .dockerignore) in favor of the BFF, matching GsmNode
- Update .claude/launch.json to run the dev server from web/
- Rewrite README.md for the new layout

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

Web App/web/src/components/PartFormModal.vue

@@ -0,0 +1,63 @@
+<script setup>
+import { ref } from "vue";
+import { api } from "../api";
+import Modal from "./Modal.vue";
+
+const props = defineProps({
+  carId: { type: String, required: true },
+  part: { type: Object, default: null },
+});
+const emit = defineEmits(["saved", "close"]);
+
+const isEdit = !!props.part;
+const saving = ref(false);
+const error = ref("");
+const form = ref({
+  name: props.part?.name ?? "",
+  partNumber: props.part?.partNumber ?? "",
+  category: props.part?.category ?? "",
+});
+
+async function submit() {
+  saving.value = true;
+  error.value = "";
+  try {
+    const payload = {
+      car: props.carId,
+      name: form.value.name.trim(),
+      partNumber: form.value.partNumber.trim(),
+      category: form.value.category.trim(),
+    };
+    const saved = isEdit
+      ? await api.updatePart(props.part.id, payload)
+      : await api.createPart(payload);
+    emit("saved", saved);
+  } catch (e) {
+    error.value = e.message;
+  } finally {
+    saving.value = false;
+  }
+}
+</script>
+
+<template>
+  <Modal :title="isEdit ? 'Edit part' : 'Add part'" @close="emit('close')">
+    <p v-if="error" class="mb-3 rounded-control bg-danger-soft px-3 py-2 text-sm font-medium text-danger">{{ error }}</p>
+    <form class="space-y-3" @submit.prevent="submit">
+      <div>
+        <label class="dh-label">Part name *</label>
+        <input v-model="form.name" required placeholder="Oil Filter" class="dh-input" />
+      </div>
+      <div>
+        <label class="dh-label">Part number</label>
+        <input v-model="form.partNumber" placeholder="04152-YZZA7" class="dh-input data" />
+      </div>
+      <div class="mt-4 flex justify-end gap-2">
+        <button type="button" class="dh-btn dh-btn-ghost" @click="emit('close')">Cancel</button>
+        <button type="submit" :disabled="saving" class="dh-btn dh-btn-primary">
+          {{ saving ? "Saving…" : isEdit ? "Save changes" : "Add part" }}
+        </button>
+      </div>
+    </form>
+  </Modal>
+</template>