fix(server): create SQLite database file if missing on first start

SqlitePool::connect defaults create_if_missing=false in SQLx 0.8, causing
SQLITE_CANTOPEN (error 14) when the PVC is empty on first deploy.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

solitaire_server/src/main.rs

@@ -32,9 +32,10 @@
 //! ```
 
 use solitaire_server::{build_router, AppState};
-use sqlx::SqlitePool;
+use sqlx::{sqlite::SqliteConnectOptions, SqlitePool};
 use std::{
     io::{self, BufRead},
+    str::FromStr,
     net::SocketAddr,
 };
 
@@ -64,7 +65,11 @@ async fn main() {
 async fn run_reset_password(username: &str) {
     let db_url = std::env::var("DATABASE_URL").expect("DATABASE_URL must be set");
 
-    let pool = SqlitePool::connect(&db_url)
+    let pool = SqlitePool::connect_with(
+        SqliteConnectOptions::from_str(&db_url)
+            .expect("invalid DATABASE_URL")
+            .create_if_missing(true),
+    )
     .await
     .expect("failed to connect to database");
 
@@ -105,7 +110,11 @@ async fn run_server() {
         .parse()
         .expect("SERVER_PORT must be a valid port number");
 
-    let pool = SqlitePool::connect(&db_url)
+    let pool = SqlitePool::connect_with(
+        SqliteConnectOptions::from_str(&db_url)
+            .expect("invalid DATABASE_URL")
+            .create_if_missing(true),
+    )
     .await
     .expect("failed to connect to database");