fix(downloads): a suspended user's queued jobs wait, and a clip too big for the space left says so

A suspension now blocks the user's downloads as quota.resolve already advised: the worker leaves
their queued jobs unclaimed until it is lifted (the confirm says so). A cut clip larger than the
remaining storage is refused with its own message (not "storage is full"), and a clip's quota
refusal reads as a clip's in both languages. The cancel poll compares to JobStatus.RUNNING.

backend/app/models.py

@@ -123,7 +123,8 @@ class User(Base, TimestampMixin, CanonicalEmailMixin):
     is_active: Mapped[bool] = mapped_column(Boolean, default=True, server_default="true")
     # Admin-imposed access block, distinct from is_active (approval lifecycle). A suspended
     # account can't sign in by any method and its live sessions are rejected; the user is told
-    # why and pointed at the operator's contact.
+    # why and pointed at the operator's contact. The worker leaves its queued downloads unclaimed
+    # until the block is lifted (`worker._claim_job`).
     is_suspended: Mapped[bool] = mapped_column(Boolean, default=False, server_default="false")
     # Server-side session revocation (SA4): a monotonic counter bumped on password reset, password
     # change, or "log out everywhere". A signed session cookie records the epoch it was minted under;