feat(sdk): guard the delete organization flow - #1881

The delete button greys out while the org has open invoices with a
non-zero amount, and its hover tooltip says to pay them from the
billing page first — the server refuses the delete in that state
anyway, this stops the user before the failed call.

The delete dialog warns when tokens remain on the billing account:
deleting forfeits them, and support can transfer the amount to the
user's bank account. Confirming the dialog is the user's consent.

The confirm button also disables while the request is in flight, so
repeated clicks cannot fire the delete twice, and a failed_precondition
response shows the server's reasons instead of a generic error.

The delete button now asks the server directly whether a delete would
go through (CheckOrganizationDelete, added in #1894)
instead of inferring one blocker from the invoice list. The button
greys out for every blocker the real delete would refuse with — a paid
subscription to downgrade, unpaid invoices, a token debt — and the
tooltip shows one short instruction per kind of blocker, with counts
for invoices and a fallback to the server's message for kinds this
version does not know. While the check loads the button stays disabled;
a failed check fails open since the server refuses independently.

@raystack/proton moves to the proton main commit that ships the RPC.
The shared open-invoice filters stay for the billing page's
payment-issue banner.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

isLoading is false when a reopened dialog refetches over cached data,
so a stale balance could show while the confirm was already clickable.
The guard now keys off isFetching, which covers the initial load and
every refetch.

When a delete is refused, the toast now shows the same short
instructions the tooltip uses, built from the blocker types in the
error's PreconditionFailure detail (read from the Connect JSON debug
payload). Blocker kinds this version does not know, unreadable details,
and every other unexpected error show a generic message instead of the
raw server text, which carried internal ids. The not-found toast says
plainly that the organization no longer exists. The instruction mapping
moved to one shared helper used by both the tooltip and the toast.

Telling the user to contact support made the settlement their job. The
balance is settled by the operator, so the message now says the support
team will reach out to them. The wording stays generic on purpose: this
code runs for any deployment, so it names no product or company.

Showing the number of tokens pending settlement has tax implications,
so the warning no longer names an amount. It says the organization
still has unused tokens, that deleting forfeits them, and that the
support team will reach out to settle any that were purchased. The
balance is still fetched, but only to decide whether to show the
warning at all.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Nothing in the gap touches this package: the removed deprecated
permission fields belong to PermissionRequestBody, which the client SDK
never uses.