upgrade: adopt V8.34.1 (multi-image banner carousel + spec-table source modes)

Plain overlay (33 items, same-source lineage, zero patch replay).
Theme suites 35/35; full run 453 passed + 10 known Windows env fails
(suspect-module rerun confirms identical failure set).
Live: container 8.34.1-dev.1; hesupipe home leftover industrial-preset
blocks cleared via studio draft+publish flow — home now renders pure
trade-pro template (sf-section/Chinese blocks = 0).

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

scripts/verify_release.py

@@ -6,7 +6,7 @@ import sys
 ROOT=Path(__file__).resolve().parent.parent
 sys.path.insert(0,str(ROOT))
 from app.version import VERSION
-assert VERSION=='8.33.1-dev.1'
+assert VERSION=='8.34.1-dev.1'
 api=(ROOT/'app'/'main.py').read_text(encoding='utf-8')
 assert 'return builder.build(' not in api, 'A synchronous request-thread build has reappeared'
 assert "@app.post('/api/sites/{site_id}/builds', status_code=202)" in api