[NafisAli]

Summary

This PR fixes a bug in save-file validation where nms-save asserted that both BaseContext and ExpeditionContext must always be present in the save file JSON.

In vanilla No Man's Sky saves:

• Standard / primary saves that have never joined an expedition (ActiveContext: "Main") only have BaseContext; ExpeditionContext is omitted entirely.
• Standalone expedition saves (ActiveContext: "Season") only have ExpeditionContext; BaseContext is omitted entirely.

Previously, attempting to load a standard save without ExpeditionContext resulted in:

Error loading save: missing required address value at /ExpeditionContext

And attempting to load a standalone expedition save resulted in:

Error loading save: missing required address value at /BaseContext

Changes

1. crates/nms-save/src/validated.rs:
   • Updated context_value and validate_context so that inactive context objects are optional (Option<&Map<String, Value>>).
   • If an inactive context is absent from the JSON, default addresses are used without failing validation.
   • Added "Season" to the check for active_is_expedition.
2. crates/nms-save/src/model.rs:
   • Added #[serde(default)] to base_context and expedition_context in SaveRoot.
   • Added #[serde(default = "default_active_context")] to active_context in SaveRoot.
3. crates/nms-save/src/convert.rs:
   • Added "Season" to active_player_state() context matcher alongside "Expedition".
4. crates/nms-save/tests/validated_save.rs:
   • Added test coverage for saves with missing inactive contexts (test_checked_parser_accepts_saves_with_only_active_context).
   • Adjusted test_checked_parser_keeps_active_selector_and_required_context_container_rules so only the active context is asserted as required.

Testing

• Ran all unit and integration tests across the workspace (cargo test --workspace): all passed.
• Validated against multiple real game saves (vanilla Main saves with no expedition history and Season saves).