resolve_quota only ever reported the caller's personal envelope,
ignoring the drive_id already resolved at every PROPFIND call site —
shared drives with their own quota showed the wrong numbers. Adds
AppState::resolve_webdav_quota, shared by both WebDAV surfaces:
nil drive_id or personal drive -> account envelope, shared drive ->
its own storage.drives quota/used_bytes.
Also adds quota-used-bytes/quota-available-bytes to the NextCloud-
compatible surface, which previously had no RFC 4331 support at all.
Registers webdav_quota_properties.hurl and the new
nc_webdav_quota_properties.hurl in tests/api/run.sh — neither was
wired into the suite before this change.
Threads the caller's account-wide (used, available) storage figures through
PROPFIND for the plain-file WebDAV surface, resolved once per request via
StorageUsagePort::get_user_storage_info and reused for every folder entry
in the response. Unlimited accounts (quota <= 0) omit quota-available-bytes
entirely per RFC 4331 §3, rather than disclosing a sentinel value.
Properties are only advertised as known when the quota subsystem is enabled
and the lookup succeeds; otherwise they fall through to the standard 404
propstat.
M.Schmidt