docs(wiki): record session findings — snapshot fix, booth rework, db reset

- entry-exit-points.md: the snapshot content-type bug + serve-side cleanType
  fix (Hikvision image/jpeg; charset="UTF-8" broke every legacy render).
- booth-exit-flow.md: the Active-Sessions/modal rework — inline barrier button
  removed -> modal; closed-within-grace view; live grace countdown; actual paid
  amount; read-only snapshot review in the closed-session view.
- local-dev-workflow.md: the gated `pnpm db:reset` training tool + flag table +
  the booth (docker exec, no pnpm) note.
- appliance-provisioning.md: new §7d — reset on the booth via docker exec into
  the server container (script ships in the deploy bundle; DATABASE_URL=
  /data/parking.sqlite), ledger-truncation warning + the two safety gates.
- index.md catalog line; log.md entries.

Claude-Session: https://claude.ai/code/session_01Xcm6ikLgGoCxxHrxtjkk5V

wiki/index.md

@@ -111,7 +111,7 @@ Counts: 4 sources · 19 entities · 46 concepts · 7 decision records.
 - [[i18n]] — Albanian default + English; per-user server-stored language preference (users.language), loaded on login; tickets stay Albanian.
 
 ## Dev environment (reference)
-- [[local-dev-workflow]] — running the stack locally; setup, the dev-hang gotchas, seed:admin.
+- [[local-dev-workflow]] — running the stack locally; setup, the dev-hang gotchas, seed:admin, the gated `db:reset` training/demo tool.
 - [[wsl-dev-networking]] — WSL2 NAT blocks device broadcast; use mirrored mode + the gotchas after.
 
 ## Decisions