dev/e2e: disposable server for app e2e / agent UI testing

`dev/e2e/e2e.sh up` runs an isolated ImageApi (port 8090, own build dir,
db, thumbnails, HLS) next to a real local server, serving a copy of a
synthetic fixture library. Every fixture image has its path, date and
scenario burned into the pixels; manifest.json records expected dates,
GPS, cameras, tags and counts. `reset` restores the baseline.

- LOCAL_BIND_URL makes the hardcoded localhost:8088 listener
  configurable (default unchanged; empty disables it) so a second
  instance can start.
- create_user bin: the server has no registration route; idempotent.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/bin/create_user.rs

@@ -0,0 +1,40 @@
+//! Create a login user. The server has no registration route, so this is
+//! how a fresh database (e.g. the `dev/e2e` harness) gets its first account.
+//!
+//! Idempotent: an existing username is left untouched and reported, so the
+//! harness can re-run it on every reset. Runs pending migrations first so it
+//! works against a database the server has never opened.
+//!
+//! Usage: `create_user <username> <password>` (reads `DATABASE_URL` from
+//! `.env` / the environment like the server does).
+
+use anyhow::{Result, bail};
+use diesel_migrations::{EmbeddedMigrations, MigrationHarness, embed_migrations};
+use image_api::connect;
+use image_api::database::{SqliteUserDao, UserDao};
+
+const MIGRATIONS: EmbeddedMigrations = embed_migrations!();
+
+fn main() -> Result<()> {
+    dotenv::dotenv().ok();
+
+    let args: Vec<String> = std::env::args().skip(1).collect();
+    let [username, password] = args.as_slice() else {
+        bail!("usage: create_user <username> <password>");
+    };
+
+    connect()
+        .run_pending_migrations(MIGRATIONS)
+        .map_err(|e| anyhow::anyhow!("failed to run migrations: {e}"))?;
+
+    let mut dao = SqliteUserDao::new();
+    if dao.user_exists(username) {
+        println!("user '{username}' already exists; leaving it unchanged");
+        return Ok(());
+    }
+    match dao.create_user(username, password) {
+        Some(_) => println!("created user '{username}'"),
+        None => bail!("failed to create user '{username}'"),
+    }
+    Ok(())
+}