fix: use correct SQLite DSN format to prevent file creation

- Change `sqlite::memory:` to `:memory:` in all test configs
- Add special handling in Driver() for SQLite DSNs without scheme
  (:memory:, .db, .sqlite files)

The previous `sqlite::memory:` format was being interpreted as a file
path by the SQLite driver, causing unwanted file creation.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: mpyw

SCHEMA.md

@@ -1,5 +1,5 @@
 database:
-  dsn: "sqlite::memory:"
+  dsn: ":memory:"
 
 mutations:
   - type: one

e2e/content_type_default_test.yaml

@@ -1,5 +1,5 @@
 database:
-  dsn: "sqlite::memory:"
+  dsn: ":memory:"
 
 mutations:
   - type: one

e2e/content_type_form_test.yaml

@@ -1,5 +1,5 @@
 database:
-  dsn: "sqlite::memory:"
+  dsn: ":memory:"
 
 mutations:
   - type: one

e2e/content_type_json_test.yaml

@@ -71,7 +71,7 @@ func TestDatabaseInit_SQLFile(t *testing.T) {
 	configFile := filepath.Join(tmpDir, "config.yaml")
 	err = os.WriteFile(configFile, []byte(`
 database:
-  dsn: "sqlite::memory:"
+  dsn: ":memory:"
   init:
     sql_files:
       - ./init.sql

e2e/database_init_test.go

@@ -1,5 +1,5 @@
 database:
-  dsn: "sqlite::memory:"
+  dsn: ":memory:"
   init: |
     CREATE TABLE IF NOT EXISTS products (
       id INTEGER PRIMARY KEY,

e2e/database_init_test.yaml

@@ -1,5 +1,5 @@
 database:
-  dsn: "sqlite::memory:"
+  dsn: ":memory:"
   init: |
     CREATE TABLE IF NOT EXISTS resources (
       id INTEGER PRIMARY KEY AUTOINCREMENT,

e2e/empty_body_test.yaml

@@ -1,5 +1,5 @@
 database:
-  dsn: "sqlite::memory:"
+  dsn: ":memory:"
 
 queries:
   - type: one

e2e/invalid_csv_with_one_test.yaml

@@ -1,5 +1,5 @@
 database:
-  dsn: "sqlite::memory:"
+  dsn: ":memory:"
 
 queries:
   - type: one

e2e/invalid_each_with_one_test.yaml

@@ -1,5 +1,5 @@
 database:
-  dsn: "sqlite::memory:"
+  dsn: ":memory:"
 
 queries:
   - type: many