feat(identity): local-feature matcher plus text lane as the default backend

Replaces the DINO gallery as the recognition path with the measured design
from docs/research/2026-09-28-recognition-architecture/DECISION.md: RootSIFT
over a per-SKU reference pyramid, similarity-constrained RANSAC and a hue
check, fused with an OCR text lane that vetoes a match whose package text
names a different catalog row and answers on its own when geometry finds
nothing.

- identity_lanes.py: LocalLane, TextLane, DecisionPolicy. The text lane
  builds each row's signature from the catalog name plus its packshot OCR, so
  a row with no enrolled image is still answerable.
- engine.py: every backend groups scores by canonical SKU, so no
  view-suffixed id reaches the wire and a name and price always resolve.
  decide_crop fuses the lanes; score_crop_lanes feeds the live path. Both
  lanes are built in warm_up (non-fatally) so the first frame is not the slow
  one, and the text lane shares the engine's OCR lock.
- live.py: decides per crop on the lane's own rank order. The lane's order
  comes from its rank key and its value is only the gate, so re-sorting by
  value named a different SKU than the lane chose; averaging in an empty
  observation also diluted a good confidence below the accept line.
- identity.py: a `local` score scale whose gate is one absolute line, because
  the value is already a margin over the runner-up.
- app.py, run-demo-server.sh: `--identity local` is the default; the demo
  server no longer starts on the leaked `stock-lopia` catalog.
- eval_live.py: the replay vocabulary accepts `local`, so a recording from
  the shipped server can be scored.
- README.md: documents the three backends and what each is for.

Measured on the corrected image6 labels at live resolution: 36/61 in-catalog
facings named at 95% precision, 0 of 48 unknowns accepted, 11 labels sourced
from the text lane alone. Through the real server: /v1/recognize 90%
precision, /v1/stream 100% precision, no view-suffixed ids on either.

recognization/stock-lopia-clean/stock.csv

@@ -0,0 +1,13 @@
+SKU_ID,product_name,receipt_date,expiration_date,number_in,number_out,number_on,image_link,price
+sku_l01,キューピー エッグケア 305g,2026-09-18,2026-12-20,36,12,24,'',349
+sku_l02,キューピー アマニ油マヨネーズ 200g,2026-09-18,2026-12-20,24,9,15,'',329
+sku_l03,キューピー からしマヨネーズ 200g,2026-09-18,2026-12-20,30,14,16,'',219
+sku_l04,やまや めんたいマヨネーズタイプ 200g,2026-09-18,2026-11-30,18,6,12,'',399
+sku_l05,キューピー ゼロ ノンコレステロール 310g,2026-09-20,2026-12-25,24,11,13,'',269
+sku_l06,キューピー フィッテ 210g,2026-09-20,2026-12-25,18,7,11,'',379
+sku_l07,丸和油脂 ラッキーマヨネーズ 200g,2026-09-20,2026-12-25,24,10,14,'',199
+sku_l08,スパイシーストーム ペリペリミックス 30g,2026-09-15,2027-03-15,12,4,8,'',699
+sku_l09,ピュアセレクト コクうま カロリーカット65% 360g,2026-09-22,2026-12-28,30,13,17,'',209
+sku_l10,ピュアセレクト マヨネーズ 450g,2026-09-22,2026-12-28,36,15,21,'',222
+sku_l11,キューピー ハーフマヨネーズ 450g,2026-09-19,2026-12-22,48,22,26,'',269
+sku_l12,焼肉のたれ 中辛,2026-09-10,2027-02-10,24,8,16,'',299