Resize a file share's provisioned capacity

Changes the provisioned capacity of the selected file share (the file share detail page "Resize" action). The new size must respect the platform minimum and may not be smaller than the share's current used capacity (usedGb); growing also re-derives the tier's provisioned IOPS/throughput envelope and the hourly billing for provisioned capacity. On acceptance the share enters the UPDATING state while the underlying filesystem is extended; clients stay mounted throughout. Validation: fileShareId must reference a live share (→ 404 NOT_FOUND); the share must be in a state that permits resize (AVAILABLE, or ERROR when the share exists in the backing file service — the resize reads the provider's real state, so it is also the way to recover an ERROR share the provider holds healthy; CREATING/UPDATING, or an ERROR share that was never provisioned → 409 CONFLICT); provisionedGb ≥ 100 and ≥ current usedGb (shrink below used data → 422 VALIDATION_ERROR); the resulting capacity must fit the scope quota (→ 409 QUOTA_EXCEEDED) and regional tier capacity (→ 409 CAPACITY_UNAVAILABLE). RBAC: owner|admin|contributor. Async & state: Asynchronous; returns 202 with an Operation resource. The share transitions AVAILABLE|ERROR → UPDATING → AVAILABLE (or → ERROR on failure); resource.updated SSE frames with kind "storage.file_share" patch status, provisionedGb, iops, throughputMbps, updatedAt and, when the provider reports it, mountPath. When the provider has not finished the resize by the time the worker stops waiting, the share lands ERROR (Operation FAILED) and keeps being re-checked in the background (shortly after, then periodically): if the provider reports the share healthy, it returns to AVAILABLE at the provider's actual size (a resource.updated frame carries the healed fields). A resize of an ERROR share never shrinks a share the provider already holds larger than the requested size; it settles the share at its actual size instead. Errors: 401 unauthenticated; 403 insufficient role; 404 unknown scopeId or fileShareId; 409 CONFLICT share not in a resizable state; 409 QUOTA_EXCEEDED scope capacity quota; 409 CAPACITY_UNAVAILABLE no regional capacity; 412 If-Match mismatch; 422 invalid target size; 500 unexpected failure. Idempotency/Concurrency: Idempotency-Key is optional (recommended); replaying the same key returns the original 202 Operation without applying the resize twice. If-Match pins the resize to the share revision the user saw (mismatch → 412).