libpanto API fixes

- FSJSONLStore: don't require `cwd`, instead panto CLI provides it in
  the session metadata
- Lua: expose the `SessionStore` interface and the `FSJSONLStore` and
  `NullStore` implementations
- C: use idiomatic `const char *` for incoming strings
- C: expose the `FSJSONLStore` and `NullStore` implementations

1 files changed, 3 insertions, 1 deletions

diff --git a/src/main.zig b/src/main.zig
index 06fd29e..693e88c 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -251,7 +251,9 @@ pub fn main(init: std.process.Init) !void {
     // per-cwd `session_dir` (the CLI owns the cwd→dir grouping; the store
     // is cwd-agnostic). Must outlive the agent, which appends through a
     // `Session` handle minted/resolved below.
-    var session_store_impl = try panto.FileSystemJSONLStore.init(alloc, io, session_dir, cwd);
+    const session_metadata = try std.fmt.allocPrint(alloc, "{{\"cwd\":{s}}}", .{try std.json.Stringify.valueAlloc(alloc, cwd, .{})});
+    defer alloc.free(session_metadata);
+    var session_store_impl = try panto.FileSystemJSONLStore.initWithMetadata(alloc, io, session_dir, session_metadata);
     defer session_store_impl.deinit();
     const session_store = session_store_impl.store();