dev: add parallel dev environment under /docker/dev

Near-1:1 clone of the prod remote-access stack, isolated on a new external
dev_edge network and fronted by the same shared Caddy instance (dual-homed on
edge + dev_edge). Dev is manual-start (not on boot).

- Hostnames: app-dev / api-dev .linumiq.net, tunnels under *.dev.linumiq.net,
  dev tunnel ingress on port 7001.
- Dev Supabase (project supabase-dev, *-dev containers), web, frps, redis,
  stripe-stub, bandwidth-worker with fresh independent secrets (gitignored).
- Shared Caddyfile: app-dev -> web-dev, api-dev -> dev kong (+webhook block),
  *.dev -> frps-dev vhost. Caddy compose dual-homed on dev_edge.
- On-demand-TLS authorizer (prod check-subdomain, in gitignored volumes/)
  extended additively: app-dev/api-dev -> 200; *.dev delegated to the dev
  authorizer. Prod allow-list logic unchanged.
- dev.sh manual up/down/ps helper; README documents topology + secrets.

Secrets, frps.toml, volumes/, web worktree and data dirs are gitignored.

.gitignore

@@ -9,3 +9,12 @@
 /frps/frps.toml
 /.remediation-backup/
 /up.sh
+
+# Dev environment (mirror of prod ignores; keep secrets/data/volumes out of git)
+/dev/web/
+/dev/.dev-secrets.env
+/dev/frps/frps.toml
+/dev/supabase/volumes/
+/dev/redis/data/
+/dev/stripe-stub/.env
+/dev/bandwidth-worker/.env