feat: a live path that uses the enrolled store, and a demo server a phone can reach

The live session scored crops with the matcher regardless of the configured identity
backend, so a live scan used the old mechanism while the still path used the enrolled
gallery - measured, the matcher accepts look-alikes and cannot say "unknown", which is
exactly what a real shelf needs it to do. score_crop now routes to the gallery, and
the decision uses a similarity scale (accept at 0.60 with a 0.04 margin) rather than
inlier-count thresholds that mean nothing on a cosine.

The synthetic walk is gone: demo.py, demo_replay.py, the /v1/demo endpoints and the
walk benchmark are deleted, and the app's frame source is the camera on a device (the
single-image replay stays for the simulator, which has no camera).

stock-demo merges both demo shelves (27 products, 62 views, trained head) so one
server recognises either image, and run-demo-server.sh starts it bound to 0.0.0.0 and
prints the exact URL to put in Config.xcconfig.

Verified over the LAN with 1280x960 frames: 40 frames in 5.3s, 9 products recognised
on demo image 1.

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

recognization/stock-demo/stock.csv

@@ -0,0 +1,28 @@
+SKU_ID,product_name,receipt_date,expiration_date,number_in,number_out,number_on,image_link,price
+sku_m01,小岩井 低脂肪牛乳,2026-09-25,2026-10-20,24,8,16,'',186
+sku_m02,荻山酪農 カフェ・オ・レ,2026-09-25,2026-10-20,24,8,16,'',397
+sku_m03,丹那 3.6牛乳,2026-09-25,2026-10-20,24,8,16,'',214
+sku_m04,木次 ミルクコーヒー,2026-09-25,2026-10-20,24,8,16,'',195
+sku_m05,木次 パスチャライズ牛乳,2026-09-25,2026-10-20,24,8,16,'',240
+sku_m06,キスキ ブラウン・スイス牛乳,2026-09-25,2026-10-20,24,8,16,'',254
+sku_m07,丹那 飲んでやさしいヨーグルト,2026-09-25,2026-10-20,24,8,16,'',225
+sku_m08,農場3.7牛乳 特選,2026-09-25,2026-10-20,24,8,16,'',216
+sku_m09,MINOR FIGURES OAT,2026-09-25,2026-10-20,24,8,16,'',300
+sku_m10,北海道 低脂肪乳,2026-09-25,2026-10-20,24,8,16,'',214
+sku_m11,タカナシ 低温殺菌牛乳,2026-09-25,2026-10-20,24,8,16,'',396
+sku_m12,RUDE HEALTH Oat Organic,2026-09-25,2026-10-20,24,8,16,'',400
+sku_m13,小岩井 無脂肪牛乳,2026-09-25,2026-10-20,24,8,16,'',178
+sku_m14,きすき ノンホモ牛乳,2026-09-25,2026-10-20,24,8,16,'',198
+sku_k01,明治 おいしい牛乳,2026-09-25,2026-10-15,48,20,28,'',198
+sku_k02,ゆうパック 優良牛乳,2026-09-25,2026-10-15,48,20,28,'',130
+sku_k03,酪農家限定 低温殺菌牛乳,2026-09-25,2026-10-15,48,20,28,'',248
+sku_k04,北海道牛乳,2026-09-25,2026-10-15,48,20,28,'',178
+sku_k05,MEGMILK,2026-09-25,2026-10-15,48,20,28,'',158
+sku_k06,毎日牛乳,2026-09-25,2026-10-15,48,20,28,'',168
+sku_k07,タカナシ 低温殺菌牛乳,2026-09-25,2026-10-15,48,20,28,'',258
+sku_k08,タカナシ 殺菌低脂肪牛乳,2026-09-25,2026-10-15,48,20,28,'',198
+sku_k09,毎日骨太,2026-09-25,2026-10-15,48,20,28,'',148
+sku_k10,カルシウム入り低脂肪乳,2026-09-25,2026-10-15,48,20,28,'',145
+sku_k11,無脂肪牛乳,2026-09-25,2026-10-15,48,20,28,'',138
+sku_k12,低脂肪牛乳,2026-09-25,2026-10-15,48,20,28,'',120
+sku_k13,ミルク,2026-09-25,2026-10-15,48,20,28,'',260