Multi-cloud NodeLink storage provisioning and management

Goal: a NodeLink on EFS, Filestore or Azure Files provisions, mounts, bills visibly and can be removed — all from the console, in that cloud's own words. - GCP Filestore provisions in us-central1 (fall back to an available tier/capacity; cost note matches what is created; capacity refusals say what to change). - Storage tab, status rows and provisioning strip use the store's own cloud terms; re-choosing storage on a failed NodeLink offers its own cloud first; Retry refreshes steps and error without reload. - Storage shows tier and size once ready; Delete on a storage (refused while used; removes a Jaah-created EFS with its mount targets/SG, or a Jaah-created Filestore when the user ticks "also delete", off by default; adopted stores never deleted). Delete dialog mentions billed files only when storage exists. - Add node offers only ready NodeLinks on the connection's cloud; birth doors (`nodelinks.birth_set`, node-group sets) refuse another cloud's storage with the live-attach 409 text. - "Share subscriptions" shows which nodes it attaches before Create, with untick. - `OUT_OF_VPC` reason points to the reader docs page, not a repo path. - Clean up Org B's leftover EFS fs-03ce9c15eee27deea (GMind, us-east-1) through the new Delete. Out of scope: macOS NodeLink (own task); Windows NodeLink verification (Windows task). Done means: on dev a Filestore NodeLink provisions, mounts on two GCP nodes, and is deleted from the console (gone in GCP); tests pin cloud refusal, delete requests, per-provider labels; no AWS terms on a Filestore NodeLink at 1280/390.

Multi-cloud NodeLink storage merged (#6636, plus fixes #6643 and #6645) and deployed. On dev a Filestore was provisioned, then deleted in GCP from the console, and Org B's EFS was cleaned up. Mounting on GCP nodes is blocked by the EFS-only host helper (draft #9138). Visual check at 1280/390 shows GCP terms only. Memory: none applied.