fix: give the roster's column zip an explicit strict=False (387 D1, B905)

ef91fcf failed ruff's B905 lane on one zip(labels, cells) without strict=. Tests, integration and the frontend were already green on that SHA.

strict=False is the deliberate side, not the quiet one. strict=True raises a bare ValueError - not SubscribeStarDriftError - and would fail the whole roster sync over a column mismatch in `details`, which nothing reads yet. That would take down reconciliation and the gated-post reasons over a cosmetic markup change, while creator identity (id, slug) never depended on the columns at all.

But a shifted column would mislabel details silently (a price filed under "discord"), so a count mismatch now logs a canary warning, mirroring the feed parser's existing parse canary: diagnosable from the worker log, never fatal.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SHQB1YukL3VyvMK8rcbmV9

backend/app/services/subscribestar_client.py

@@ -396,6 +396,16 @@ def _roster_rows(table: str, identifier: str, base: str) -> list[Membership]:
         name = _ROSTER_NAME_RE.search(row)
         slug = unescape(href.group(1))
         cells = _ROSTER_CELL_RE.findall(row)
+        if len(cells) != len(labels):
+            # Canary, not a refusal. Identity above does not depend on columns,
+            # so a shifted column must not fail the whole roster — but it would
+            # silently mislabel `details` (a price filed under "discord"), so
+            # say so in the worker log where it is diagnosable.
+            log.warning(
+                "SubscribeStar roster %r: %d cells against %d headers — column "
+                "details may be mislabelled; markup likely changed (note #3989)",
+                identifier, len(cells), len(labels),
+            )
         rows.append(Membership(
             campaign_id=user_id.group(1),
             display_name=(_cell_text(name.group(1)) if name else "") or None,
@@ -420,7 +430,7 @@ def _roster_rows(table: str, identifier: str, base: str) -> list[Membership]:
                 # its <th>'s class at all.
                 "columns": {
                     label: _cell_text(cell)
-                    for label, cell in zip(labels, cells)
+                    for label, cell in zip(labels, cells, strict=False)
                     if label not in _ROSTER_SKIP_COLUMNS
                 },
             },