fix(infra): pass pgweb credentials via discrete CLI flags (#63)

## Summary

`PGWEB_DATABASE_URL` (post-#62 rename) still fails at boot:

```
Error: Invalid URL. Valid format: postgres://user:password@host:port/db?sslmode=mode
```

Root cause: the userinfo portion of a Postgres URL must be URL-encoded — any `@`, `#`, `:`, `/`, `?`, `%`, `&`, `=`, `+`, `;` etc. in the password breaks the parser. Compose has no built-in URL encoding, so the URL we construct in YAML is fragile by design and depends on the developer happening to pick a URL-safe password.

Switch to pgweb's discrete CLI flags (`--host`, `--port`, `--user`, `--pass`, `--db`, `--ssl`). Compose interpolates each value literally — no URL encoding required, any password works.

The image's ENTRYPOINT already passes `--bind=0.0.0.0 --listen=8081`; our args are appended to those.

## Side benefit

A missing password now yields an explicit Compose error (`POSTGRES_PASSWORD must be set in infra/local/.env`) rather than an opaque pgweb crash with a vague "Invalid URL" message.

## Test plan

- [ ] After merge: `docker compose -f infra/local/dev.compose.yml --profile dbtools up -d` → pgweb stays up (no `Restarting (1)` loop).
- [ ] http://localhost:8081 loads pgweb's UI; you can navigate to the `audit` schema.
- [ ] Confirm with a password that contains a special char (e.g., `dev@pass#2026!`) — should still work.

---------

Co-authored-by: Julien Gautier <julien.gautier@apf.asso.fr>
Reviewed-on: #63

infra/local/dev.compose.yml

@@ -102,11 +102,20 @@ services:
     container_name: apf-portal-pgweb
     restart: unless-stopped
     profiles: [dbtools]
-    environment:
+    # Use discrete CLI flags rather than `PGWEB_DATABASE_URL`. The URL
-      # `PGWEB_DATABASE_URL` (formerly `DATABASE_URL`) — pgweb 0.16
+    # form is fragile: any special character in POSTGRES_PASSWORD
-      # deprecated the old name, ignores it, and starts up empty,
+    # (`@`, `#`, `:`, `/`, `?`, `%`, `&`, …) breaks the userinfo
-      # crashing with "Invalid URL".
+    # parser, and the resulting "Invalid URL" error is opaque. Discrete
-      PGWEB_DATABASE_URL: postgres://${POSTGRES_USER:-portal}:${POSTGRES_PASSWORD}@postgres:5432/${POSTGRES_DB:-portal_dev}?sslmode=disable
+    # flags accept any password verbatim. The image's ENTRYPOINT
+    # already passes `--bind=0.0.0.0 --listen=8081`; these args are
+    # appended.
+    command:
+      - --host=postgres
+      - --port=5432
+      - --user=${POSTGRES_USER:-portal}
+      - --pass=${POSTGRES_PASSWORD:?POSTGRES_PASSWORD must be set in infra/local/.env}
+      - --db=${POSTGRES_DB:-portal_dev}
+      - --ssl=disable
     ports:
       - '${PGWEB_PORT:-8081}:8081'
     depends_on: