CI: add sequential tag for NoteEquipTitleTest; woodpecker runs it w.o --parallel

Parallel geckodriver startup race causes a spurious permissions error when
NoteEquipTitleTest is the first FT dispatched. @tag("sequential") moves it
into test-two-browser-FTs (sequential stage) as a reusable escape hatch.

Code architected by Disco DeDisco <discodedisco@outlook.com>
Git commit message Co-Authored-By:
Claude Sonnet 4.6 <noreply@anthropic.com>

.woodpecker/main.yaml

@@ -42,6 +42,7 @@ steps:
       - cd ./src
       - python manage.py collectstatic --noinput
       - python manage.py test functional_tests --tag=two-browser
+      - python manage.py test functional_tests --tag=sequential
       - python manage.py test functional_tests --tag=channels
     when:
       - event: push

src/functional_tests/test_applet_my_notes.py

@@ -16,6 +16,7 @@ T2 (Dashboard full flow) is split across three focused tests:
 """
 import json as _json
 
+from django.test import tag
 from django.utils import timezone
 from selenium.webdriver.common.by import By
 
@@ -404,6 +405,7 @@ class StargazerNoteFromSkyPageTest(FunctionalTest):
 # Title equip — DON/DOFF buttons on the note item
 # ──────────────────────────────────────────────────────────────────────────────
 
+@tag("sequential")
 class NoteEquipTitleTest(FunctionalTest):
     """DON button equips the note title as the sitewide greeting; DOFF restores it."""