build(deps): bump go.einride.tech/sage from 0.388.0 to 0.391.1 in /.sage

Bumps [go.einride.tech/sage](https://github.com/einride/sage) from 0.388.0 to 0.391.1.
- [Release notes](https://github.com/einride/sage/releases)
- [Commits](einride/sage@v0.388.0...v0.391.1)

---
updated-dependencies:
- dependency-name: go.einride.tech/sage
  dependency-version: 0.391.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.sage/go.mod

@@ -2,4 +2,4 @@ module sage
 
 go 1.24.9
 
-require go.einride.tech/sage v0.388.0
+require go.einride.tech/sage v0.391.1

.sage/go.sum

@@ -1,2 +1,2 @@
-go.einride.tech/sage v0.388.0 h1:WVXAZcPD9pPpM7DkpJr1kqWi7h/UDDSt/OIhcjDc0tw=
-go.einride.tech/sage v0.388.0/go.mod h1:t5X6A8IrxcJV+HnP8mOo0fgvn3XgLu58C3DUMP6v35E=
+go.einride.tech/sage v0.391.1 h1:sBVdHKaAWRFL1H32Nv5BmvouvJ/6ybZpSmHGCVBlgbk=
+go.einride.tech/sage v0.391.1/go.mod h1:t5X6A8IrxcJV+HnP8mOo0fgvn3XgLu58C3DUMP6v35E=