Add mise configuration

Manages local Java and Maven versions via mise, matching the setup
in minfraud-api-java. CI is unaffected since the GitHub Actions
workflows use setup-java directly.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: oschwald

mise.lock

@@ -0,0 +1,18 @@
+[settings]
+experimental = true
+lockfile = true
+disable_backends = [
+    "asdf",
+    "vfox",
+]
+
+[tools]
+java = "latest"
+maven = "latest"
+
+[hooks]
+enter = "mise install --quiet --locked"
+
+[[watch_files]]
+patterns = ["mise.toml", "mise.lock"]
+run = "mise install --quiet --locked"