docs(wiki): merchant validations settled + as-built; scan input decided (camera paths postponed)

validation-discounts: driving cases → the settled validation-only model (all
money/paper at the booth) → setup UX/storage/RBAC → full as-built record.
DECIDED: merchant stations scan with a USB/HID barcode scanner on the
web/desktop app (hand-keying + Luhn as fallback); POSTPONED with analysis:
web getUserMedia scanning (secure-context TLS prerequisite on the LAN +
Code128-via-camera weakness → QR-on-ticket first) and a Tauri v2 Android
merchant app (native ML Kit scanning; Android build/sideload overhead +
configurable-server-URL prerequisite). Also: wsl-dev-networking gains the
mirrored-mode gotcha where a Windows-side listener makes a port EADDRINUSE
inside WSL while invisible to ss — Vite auto-increments and tauri dev's fixed
devUrl waits on the wrong port.

Claude-Session: https://claude.ai/code/session_01YYkpEsLmoQPaize5ec3oUm

wiki/index.md

@@ -99,7 +99,7 @@ Counts: 4 sources · 19 entities · 47 concepts · 8 decision records.
 - [[capacity-occupancy]] — live count = open sessions; refuse entry + FULL sign when full (soft policy); exit never blocked.
 - [[site-metadata]] — optional park identity (name, operator, VAT, address, contact) in site_config; feeds the ticket header.
 - [[valet-overcapacity]] — "full" is soft: operator may valet-accept over capacity (keys handed over, custody). Manned, deferred.
-- [[validation-discounts]] — merchant validates a ticket → signed discount event applied at fee time.
+- [[validation-discounts]] — BUILT (2026-07-13): in-park merchant (bar/lavazh) users scan-and-validate on their device (signed event, program↔user binding); booth settles NET + prints gross/discount/net; comp/time-credit/fixed/percent, caps, /setup/site panel, /validate screen.
 - [[validation-sponsorship]] — design: sponsor accounts + postpaid B2B (customers park free, business billed monthly); not a permit.
 - [[reporting-analytics]] — revenue/occupancy/stay reports + plate-search, all projections over the signed log.
 - [[clock-integrity]] — fees depend on the host clock; detect/flag backdating on an offline box.