feat(flr): windows paths, recovery-site gate, stable partition reads

Three fixes from measuring FLR against a Windows guest (ad1, VPG 'local')
instead of only the Linux one.

1. Gate FLR to locally replicated VPGs.

   FLR is performed at the VPG's RECOVERY site, because that is where the
   mount is created. A VPG replicating to a cloud ZCA has to be recovered
   through that ZCA's API, not the protected ZVM's. Supporting that
   properly means holding credentials for every ZVM/ZCA in an estate and
   routing the call, which is a real design decision, not something to
   smuggle in. Until then zerto_recover_file refuses a VPG whose
   protected site != recovery site and names the site that owns the
   operation, instead of failing later as a confusing path or mount error.

2. Windows paths are not symmetrical with Linux.

   Linux   /home/j/app.yaml  -> Volume2-Ext4%2fhome%2fj%2fapp.yaml
   Windows C:\Users\j\f.conf -> C%3a%2fUsers%2fj%2ff.conf

   On Windows the drive letter IS the partition name, so the guest path
   already carries it. The old code prepended unconditionally and built
   'C:/C:/Users/j', which could never match. resolve_flr_path now detects
   that the path already starts with the partition.

   It also returns the raw path exactly as browse reported it. Download
   accepts the raw and the decoded form, and returning raw avoids
   re-encoding by hand. Decoding is now unquote_plus, not unquote: browse
   form-encodes a space as '+' ("Program+Files"), so a basename compare
   against "Program Files" never matched. Matching tries exact first and
   only then case-insensitively, since Windows is case-insensitive and
   Linux is not.

3. Wait for partition enumeration to settle.

   A session reports mounted before the ZVM has finished identifying
   volumes, and browsing in that window returns a partial, MIS-LABELLED
   list. The same Windows VM enumerated as 'Volume4-Unknown' with no C:
   drive, then moments later as a browsable 'C%3a' holding the whole
   filesystem. Acting on the early list makes a restorable NTFS disk look
   permanently unrestorable. wait_partitions_stable polls until the list
   stops changing.

Verified against ZVM 10.x:

- CMH-AWS-4 (recovery aws-zca) refused, naming aws-zca
- C:\ad1.keytab recovered, 58 bytes
- C:\Program Files\internet explorer\sqmapi.dll recovered, 47512 bytes --
  drive letter, two spaces, nested dirs, the exact case that was broken
- Linux /home/justin/app-config.yaml still recovers, 158 bytes
- every session unmounted, unmount.ok true

Also drops a duplicate get_vpg that shadowed the existing one (F811).

pytest 32 passed (7 new).

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_016yVfC5nvZowoLFnEGWhLGn

skills/zerto-rewind/SKILL.md

@@ -37,7 +37,10 @@ A VM can be in up to three VPGs (local backup + remote DR is common). Tag all of
 
 Human must confirm. Pass `confirmed=true` only after they say yes.
 
-- Bad config / dropped file: `zerto_recover_file` from **that tag**.
+- Bad config / dropped file: `zerto_recover_file` from **that tag**. Pass the guest path
+  (`/home/j/app.yaml` or `C:\Users\j\app.conf`); the server maps it into the FLR
+  namespace. **Locally replicated VPGs only** -- FLR happens at the recovery site, so a
+  cloud-replicated VPG must be recovered from that ZCA. The tool refuses and names the site.
 - Inspect a whole VM: `zerto_offsite_clone` or `zerto_start_failover_test`.
 - Never Failover Live. Never Move. Those are DR, not rewind.