R1: move tool registry off Config onto Agent

The tool set is no longer part of the per-turn Config snapshot. Agent now
owns a ToolRegistry (created empty at init), populated via the new
Agent.registerTool / registerToolSource methods. openStream and
OpenStreamFn take the registry as an explicit parameter rather than reading
it from cfg.registry, so swapping provider/model between turns (setConfig)
no longer disturbs the tool set.

CLI migrated to register the Lua tool source onto the agent instead of a
locally-owned registry. Test harnesses updated to stage tools on the agent.

1 files changed, 5 insertions, 8 deletions

diff --git a/src/system_prompt.zig b/src/system_prompt.zig
index b5423f8..6104034 100644
--- a/src/system_prompt.zig
+++ b/src/system_prompt.zig
@@ -467,12 +467,12 @@ fn openTmpSession(arena: Allocator, root: []const u8) !panto.session_manager.Ses
     return panto.session_manager.SessionManager.init(testing.allocator, testing.io, sessions, "/cwd");
 }
 
-/// Minimal agent harness for system-prompt tests: an empty registry and a
-/// throwaway provider config, wrapping a session store and (optionally) an
-/// adopted conversation. Holds the registry/config so the agent's borrowed
-/// pointers stay valid for the agent's lifetime.
+/// Minimal agent harness for system-prompt tests: a throwaway provider
+/// config wrapping a session store and (optionally) an adopted
+/// conversation. Post-R1 the agent owns its own (empty) tool registry, so
+/// the harness only holds the config to keep the agent's borrowed pointer
+/// valid for its lifetime.
 const SPAgentHarness = struct {
-    registry: panto.ToolRegistry,
     config: panto.config.Config,
     agent: panto.agent.Agent,
 
@@ -481,17 +481,14 @@ const SPAgentHarness = struct {
         store: panto.session_store.SessionStore,
         adopted: ?panto.conversation.Conversation,
     ) void {
-        self.registry = panto.ToolRegistry.init(testing.allocator);
         self.config = .{
             .provider = .{ .openai_chat = .{ .api_key = "k", .base_url = "u", .model = "m" } },
-            .registry = &self.registry,
         };
         self.agent = panto.agent.Agent.init(testing.allocator, testing.io, &self.config, store, adopted);
     }
 
     fn deinit(self: *SPAgentHarness) void {
         self.agent.deinit();
-        self.registry.deinit();
     }
 };