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/ServiceFormModal.vue

@@ -0,0 +1,91 @@
+<script setup>
+import { ref } from "vue";
+import { api } from "../api";
+import { formatKm } from "../lib/format.js";
+import Modal from "./Modal.vue";
+
+const props = defineProps({
+  carId: { type: String, required: true },
+  car: { type: Object, default: null },
+  service: { type: Object, default: null },
+});
+const emit = defineEmits(["saved", "close"]);
+
+const isEdit = !!props.service;
+const saving = ref(false);
+const error = ref("");
+const form = ref({
+  date: props.service ? toDateInput(props.service.date) : new Date().toISOString().slice(0, 10),
+  km: props.service?.km ?? "",
+  changedOil: props.service ? props.service.changedOil : true,
+  changedEngineAirFilter: props.service ? props.service.changedEngineAirFilter : false,
+  changedCabinAirFilter: props.service ? props.service.changedCabinAirFilter : false,
+  notes: props.service?.notes ?? "",
+});
+
+function toDateInput(value) {
+  const d = new Date(value);
+  return isNaN(d) ? "" : d.toISOString().slice(0, 10);
+}
+
+async function submit() {
+  saving.value = true;
+  error.value = "";
+  try {
+    const payload = {
+      car: props.carId,
+      date: new Date(form.value.date).toISOString(),
+      km: form.value.km ? Number(form.value.km) : 0,
+      changedOil: form.value.changedOil,
+      changedEngineAirFilter: form.value.changedEngineAirFilter,
+      changedCabinAirFilter: form.value.changedCabinAirFilter,
+      notes: form.value.notes.trim(),
+    };
+    const saved = isEdit
+      ? await api.updateService(props.service.id, payload)
+      : await api.createService(payload);
+    emit("saved", saved);
+  } catch (e) {
+    error.value = e.message;
+  } finally {
+    saving.value = false;
+  }
+}
+</script>
+
+<template>
+  <Modal :title="isEdit ? 'Edit service record' : 'Add service record'" @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 class="grid grid-cols-2 gap-2">
+        <div>
+          <label class="dh-label">Date *</label>
+          <input v-model="form.date" type="date" required class="dh-input data" />
+        </div>
+        <div>
+          <label class="dh-label">Odometer (km)</label>
+          <input v-model="form.km" type="number" placeholder="16138" class="dh-input data" />
+        </div>
+      </div>
+      <fieldset class="rounded-control border border-subtle p-3">
+        <legend class="eyebrow px-1">Changed parts</legend>
+        <label class="flex items-center gap-2 py-1 text-sm text-body"><input type="checkbox" v-model="form.changedOil" class="accent-[var(--accent)]" /> Oil &amp; oil filter</label>
+        <label class="flex items-center gap-2 py-1 text-sm text-body"><input type="checkbox" v-model="form.changedEngineAirFilter" class="accent-[var(--accent)]" /> Engine air filter</label>
+        <label class="flex items-center gap-2 py-1 text-sm text-body"><input type="checkbox" v-model="form.changedCabinAirFilter" class="accent-[var(--accent)]" /> Cabin air filter</label>
+      </fieldset>
+      <div>
+        <label class="dh-label">Notes</label>
+        <input v-model="form.notes" class="dh-input" />
+      </div>
+      <p v-if="car" class="text-xs text-muted">
+        Next service date (+{{ car.serviceIntervalDays }}d) and km (+{{ formatKm(car.serviceIntervalKm) }}) are computed automatically.
+      </p>
+      <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 service" }}
+        </button>
+      </div>
+    </form>
+  </Modal>
+</template>