chore(flash-next-seat): hardlink duplicated orca shards — 76 GiB reclaimed

The PLE conversion copied 28 non-PLE shards instead of linking them, because
os.link hit EXDEV across two separate container bind mounts of the same
filesystem. Both directories sit directly on /tank, so the duplication was
recoverable.

All 28 files verified byte-identical by SHA-256 before any change -- the point
of a hardlink is that two paths become one file, so "same size" is not
sufficient evidence. Relinked with ln to a temp name followed by an atomic
rename over the target, never rm-then-ln, which would leave a window where the
file does not exist for a process that reopens it. Generated as 56 literal-path
commands rather than a loop, per the no-destructive-ops-on-a-variable-path rule.

294G apparent across the two directories -> 218G actual. Done with the seat
live and serving; it did not blink.

Records the coupling this creates: the pristine and converted directories now
SHARE INODES, so editing a shared file in place in either one changes both.
config.json and model.safetensors.index.json are deliberately excluded from
the sharing, since the conversion changed them.

Also consolidates two duplicate disk bullets left by earlier edits.

persistent-memory.d/2026-09-14-fv-seat-reorg-and-orca-blocker.md

@@ -106,11 +106,15 @@ cost decode speed, which was the standing risk of giving up FP4 tensor-core comp
   no longer exist — it is a record, not a revert. Reverting = 126 GiB re-download.
   The pristine 170 GiB `qwen38-flash-next-orcarouter-nvfp4` IS retained (redo the conversion
   from it; do not delete it without a reason).
-- Disk: ~75 GiB of non-PLE shards are duplicated between the pristine and converted orca dirs
-  (the convert's hardlinks hit EXDEV inside the container). Now that both sit directly on
-  /tank, relinking them would reclaim it — not urgent at 3.8T free.
-- Disk: the convert **copied** ~75 GiB of unchanged shards because hardlinks hit `EXDEV`
-  (separate bind mounts of the same fs). Harmless; reclaimable by relinking if /tank tightens.
+- ✅ **Disk reclaimed 2026-09-14: 76 GiB.** The 28 non-PLE shards duplicated between the
+  pristine and converted orca dirs are now **hardlinked** (294G apparent → 218G actual).
+  All 28 verified **byte-identical by SHA-256** first, then `ln` to a temp name + atomic
+  `rename` over the target — never rm-then-ln, which leaves a window with no file. Done
+  live with the seat serving; it never blinked.
+  ⚠ **The two dirs now SHARE INODES.** Editing a shared file *in place* in either dir
+  changes both. Shards are never edited in place, and `config.json` /
+  `model.safetensors.index.json` are deliberately NOT shared (the conversion changed
+  them) — but a future session must copy-then-edit, not edit in place.
 
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