Add attachments to service, maintenance, fuel and parts records

Documents already carried a single optional file: upload, download, detach,
access-checked on every request and proxied through this server, so PocketBase's
files are never public URLs. Service records, workshop visits, refills and
catalog parts all want the same thing — a receipt, an invoice, a photo of the
box — so extend it to them.

Rather than copy the document handlers four more times, lift them into one
shared layer. Every attachable collection has a car relation and a file field,
which is what lets a single set of handlers authorize and serve all of them. An
upload finishes by delegating to the collection's own GET handler, so the
response carries the full record — derived fields and all — exactly as a re-read
would. The web side gets the same treatment: one picker component and one
upload-after-save helper behind all five forms. Net effect is five features for
about the cost of the one that was already there.

Alongside:
- parts gain a notes field
- Reminders moves behind Parts catalog in the car detail tabs
- the changed-part labels spell out in full ("Oil & Oil filter" rather than
  "Oil & filter"), and the form and table now agree

The PocketBase schema must be migrated before the new attachments work:
scripts/setup-pocketbase.mjs adds the file fields and parts.notes. It is
additive and safe to re-run.

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

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

@@ -1,6 +1,8 @@
 <script setup>
 import { ref, computed } from "vue";
 import { api } from "../api";
+import { applyAttachment } from "../lib/attachment.js";
+import AttachmentField from "./AttachmentField.vue";
 import Modal from "./Modal.vue";
 
 const props = defineProps({
@@ -26,6 +28,9 @@ const form = ref({
   notes: props.entry?.notes ?? "",
 });
 
+const file = ref(null);
+const removeFile = ref(false);
+
 function toDateInput(value) {
   const d = new Date(value);
   return isNaN(d) ? "" : d.toISOString().slice(0, 10);
@@ -43,7 +48,10 @@ async function submit() {
   error.value = "";
   try {
     const saved = await (isEdit ? api.updateFuel(props.entry.id, payload()) : api.createFuel(payload()));
-    emit("saved", saved);
+    emit("saved", await applyAttachment(api.files.fuel, saved, {
+      file: file.value,
+      remove: removeFile.value,
+    }));
   } catch (e) {
     error.value = e.message;
   } finally {
@@ -121,6 +129,8 @@ function payload() {
         </div>
       </div>
 
+      <AttachmentField v-model:file="file" v-model:remove="removeFile" :record="entry" legend="Receipt" />
+
       <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">