re: control the range, segment the frames — f105/e105/e106 all match static assembly

A capture at controlled range (ship_capture_close.sh: lock a capital ship, close
on it, F10 per range band) finally draws capital-ship hulls at full detail. Two
correctness fixes were needed before the numbers meant anything:

* one F10 log is ~14 frames with no delimiter, and WV_ref^-1 . WV_p only cancels
  the camera within one frame — segment_frames splits on vertex-buffer
  recurrence, and correlate_frames cross-checks the blocks against each other
  instead of trusting a single shot;
* aggregate by consensus, not median: a stage holds several ships of one class
  sharing vertex buffers, so a block can mix two instances.

Result: f105, e105 and e106 reproduce assemble_ship to <=0.43 units in
translation and 0.000 in rotation for every part that does not move. The e106
rules generalise, and the viewer bug report now points at the viewer. Narrow
leftovers: e105_brg is missing from assemble_ship, e105_eng_01 rotation differs
by 1.711.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

docs/re/BACKLOG.md

@@ -8,7 +8,18 @@ unknown, what evidence exists, and what the first step would be. Move an item in
 
 ## Capital ships assemble wrong in the viewer
 
-**Reported:** 2026-07-30, by the user. **Status:** ❔ open, not investigated.
+**Reported:** 2026-07-30, by the user. **Status:** 🔎 **diagnosed 2026-08-10 — the
+format layer is exonerated.** Runtime captures of three classes (`f105`, `e105`,
+`e106`) at controlled range reproduce `assemble_ship` to ≤0.43 units in translation
+and to 0.000 in rotation for every part that does not move; see
+[`ship-placement-capture-generalisation.md`](ship-placement-capture-generalisation.md)
+§4. So look at **the viewer**: first that it passes `include_external = true`
+(`iso_loader.rs:4012` — with `false` an e106 loses its bridge and both nacelles,
+5 parts instead of 11), then its own transform stack. Two narrow format-side leftovers
+remain: `e105_brg` is never produced by `assemble_ship`, and `e105_eng_01`'s rotation
+differs by 1.711.
+
+The original report and its reasoning follow.
 
 The reborn viewer builds capital ships from the split XBG7 parts via
 `sylpheed-formats::ship::assemble_ship`, and they come out **wrong** — parts in the