fix: default query_parsers engine to pg_query_protobuf

[scottjacobsen]

pgdog requires the engine field in [[query_parsers]] entries and fails to start when it is missing (the QueryParser config struct has no serde default for the field), but the chart only rendered engine when set and documented it as optional.

Always render engine, defaulting to pg_query_protobuf (pgdog's default engine), so omitting it in queryParsers values no longer produces a config pgdog can't parse.

• templates/config.yaml: render engine unconditionally with a pg_query_protobuf default
• test/values-pgdog-config-extras.yaml: add an entry without engine to exercise the default
• values.yaml: document the default
• bump chart to v0.71

Verified with test/test.sh (all passing) — rendered output:

[[query_parsers]]
database = "primary"
level = "off"
engine = "pg_query_raw"
[[query_parsers]]
database = "primary_mirror"
level = "session_control_and_locks"
engine = "pg_query_protobuf"

🤖 Generated with Claude Code

[levkk]

Ooops. So sure I set a default there.

[levkk]

I did not. Let me fix this in pgdog code. We don't want this setting exposed unless absolutely necessary.

[levkk]

Fixed in pgdogdev/pgdog#1176

[scottjacobsen]

Thanks!