feat: let subscriptions be renamed from the list (#1044)

A subscription's name is captured once at subscribe time from the feed's own
title, so playlists — particularly the UULF-prefixed channel-uploads playlists
— all come back named "Videos" and stay that way. Adds an inline editor on the
Name cell, mirroring the existing title-filter edit next to it.

The update route already whitelisted `name` and update_subscription already
applied it, so this is mostly the missing UI. The backend side is validation:
the old `str(changes["name"])` accepted any type, any length and any
whitespace, for a value that is persisted and broadcast to every connected
client. validate_subscription_name now requires a string, collapses interior
whitespace to keep the label single-line, and caps it at 200 characters.

The name is display-only — it is used for the subscription list and log lines,
never for download paths — so renaming cannot move where files land.

ui/src/app/app.html

@@ -958,7 +958,33 @@
                 [disabled]="downloads.loading"
                 [attr.aria-label]="'Select subscription ' + entry[1].name" />
             </td>
-            <td>{{ entry[1].name }}</td>
+            <td>
+              @if (editingNameId === entry[0]) {
+                <div class="d-flex flex-wrap gap-1 align-items-center">
+                  <input type="text"
+                    class="form-control form-control-sm flex-grow-1"
+                    [name]="'subName' + entry[0]"
+                    [(ngModel)]="nameEditDraft"
+                    [maxlength]="subscriptionNameMaxLength"
+                    [disabled]="downloads.loading"
+                    [attr.aria-label]="'Subscription name for ' + entry[1].name" />
+                  <button type="button" class="btn btn-sm btn-outline-secondary"
+                    (click)="saveName(entry[0])"
+                    [disabled]="downloads.loading">Save</button>
+                  <button type="button" class="btn btn-sm btn-outline-secondary"
+                    (click)="cancelEditName()"
+                    [disabled]="downloads.loading">Cancel</button>
+                </div>
+              } @else {
+                <div class="d-flex flex-wrap gap-1 align-items-center">
+                  <span class="text-break">{{ entry[1].name }}</span>
+                  <button type="button" class="btn btn-link btn-sm p-0"
+                    (click)="beginEditName(entry[0], entry[1].name)"
+                    [disabled]="downloads.loading"
+                    ngbTooltip="Rename this subscription (display name only; does not affect the download folder)">Edit</button>
+                </div>
+              }
+            </td>
             <td class="text-break"><a [href]="entry[1].url" target="_blank" rel="noopener">{{ entry[1].url }}</a></td>
             <td>
               @if (editingTitleRegexId === entry[0]) {

ui/src/app/app.spec.ts

@@ -81,7 +81,10 @@ class SubscriptionsServiceStub {
     return of({});
   }
 
-  update() {
+  updateCalls: [string, unknown][] = [];
+
+  update(id: string, changes: unknown) {
+    this.updateCalls.push([id, changes]);
     return of({ status: 'ok' as const });
   }
 
@@ -315,4 +318,37 @@ describe('App', () => {
     expect(errorSpy).toHaveBeenCalledWith('Invalid subscription title filter (regex)');
     errorSpy.mockRestore();
   });
+
+  it('renames a subscription and closes the inline editor', () => {
+    const fixture = TestBed.createComponent(App);
+    const app = fixture.componentInstance;
+    const subs = TestBed.inject(SubscriptionsService) as unknown as SubscriptionsServiceStub;
+
+    app.beginEditName('sub1', 'Videos');
+    expect(app.editingNameId).toBe('sub1');
+    expect(app.nameEditDraft).toBe('Videos');
+
+    app.nameEditDraft = '  Jane uploads  ';
+    app.saveName('sub1');
+
+    expect(subs.updateCalls).toEqual([['sub1', { name: 'Jane uploads' }]]);
+    expect(app.editingNameId).toBeNull();
+  });
+
+  it('blocks renaming a subscription to an empty name', () => {
+    const toasts = TestBed.inject(ToastService);
+    const errorSpy = vi.spyOn(toasts, 'error').mockImplementation(() => undefined);
+    const fixture = TestBed.createComponent(App);
+    const app = fixture.componentInstance;
+    const subs = TestBed.inject(SubscriptionsService) as unknown as SubscriptionsServiceStub;
+
+    app.beginEditName('sub1', 'Videos');
+    app.nameEditDraft = '   ';
+    app.saveName('sub1');
+
+    expect(subs.updateCalls.length).toBe(0);
+    expect(app.editingNameId).toBe('sub1');
+    expect(errorSpy).toHaveBeenCalledWith('Subscription name must not be empty');
+    errorSpy.mockRestore();
+  });
 });

ui/src/app/app.ts

@@ -102,6 +102,9 @@ export class App implements AfterViewInit, OnInit, OnDestroy {
   skipSubscriberOnly = false;
   editingTitleRegexId: string | null = null;
   titleRegexEditDraft = '';
+  editingNameId: string | null = null;
+  nameEditDraft = '';
+  readonly subscriptionNameMaxLength = 200;
   cachedSubs: [string, SubscriptionRow][] = [];
   selectedSubscriptionIds = new Set<string>();
   checkingSubscriptionIds = new Set<string>();
@@ -663,6 +666,34 @@ export class App implements AfterViewInit, OnInit, OnDestroy {
     });
   }
 
+  beginEditName(id: string, current: string | undefined) {
+    this.editingNameId = id;
+    this.nameEditDraft = current ?? '';
+    this.cdr.markForCheck();
+  }
+
+  cancelEditName() {
+    this.editingNameId = null;
+    this.nameEditDraft = '';
+    this.cdr.markForCheck();
+  }
+
+  saveName(id: string) {
+    const name = (this.nameEditDraft || '').trim();
+    if (!name) {
+      this.toasts.error('Subscription name must not be empty');
+      return;
+    }
+    this.subscriptionsSvc.update(id, { name }).subscribe((res) => {
+      const error = this.getStatusError(res);
+      if (error) {
+        this.toasts.error(error || 'Update subscription failed');
+        return;
+      }
+      this.cancelEditName();
+    });
+  }
+
   deleteSubscription(id: string) {
     this.subscriptionsSvc.delete([id]).subscribe((res) => {
       const error = this.getStatusError(res);