test: enable WAL for sqlite integration tests (#37861)

Enable `SQLITE_JOURNAL_MODE = WAL` for the sqlite integration test
config. With modernc as the default driver, concurrent writers serialize
on SQLite's single write lock and the tail of the queue can exceed the
20s busy timeout under CI load. WAL drains the queue fast enough to stay
inside the timeout (removes rollback's fsync-per-commit and
reader-vs-commit blocking) and covers all sqlite integration tests in
one change.

---
This PR was written with the help of Claude Opus 4.7

---------

Co-authored-by: Claude (Opus 4.7) <noreply@anthropic.com>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: Giteabot <teabot@gitea.io>

.github/workflows/files-changed.yml

@@ -64,6 +64,11 @@ jobs:
               - ".golangci.yml"
               - ".editorconfig"
               - "options/locale/locale_en-US.json"
+              - "models/fixtures/**"
+              - "tests/*.ini.tmpl"
+              - "tests/gitea-repositories-meta/**"
+              - "tests/testdata/**"
+              - "tools/test-integration.sh"
 
             frontend:
               - "*.ts"

tests/sqlite.ini.tmpl

@@ -5,6 +5,7 @@ RUN_MODE = prod
 [database]
 DB_TYPE = sqlite3
 PATH    = gitea-test.db
+SQLITE_JOURNAL_MODE = WAL
 
 [indexer]
 REPO_INDEXER_ENABLED = true