agent: add /clear and /reset REPL commands

- `/clear` forgets conversation history, usage, and node IDs while
  keeping the loaded page and cookies.
- `/reset` does a full reset, starting a fresh browser session.

docs/agent.md

@@ -307,7 +307,10 @@ See [agent-script.md](agent-script.md) for the full script format reference.
   the REPL, `/verbosity <low|medium|high>` tunes the log level,
   `/effort <none|minimal|low|medium|high|xhigh>` sets the per-turn reasoning
   budget (saved to `.lp-agent.zon`), and `/usage` prints cumulative token usage
-  and the cache hit rate for the session. These are REPL-only and never recorded.
+  and the cache hit rate for the session — `/clear` forgets the conversation
+  (history, usage, recorded actions, node IDs) while keeping the loaded page and
+  cookies, and `/reset` goes further by also starting a fresh browser session,
+  dropping the page, cookies, storage, and history. These are REPL-only and never recorded.
   ```
   > /goto https://example.com
   > /findElement role=button name=Submit

src/agent/Agent.zig

@@ -321,8 +321,7 @@ pub fn init(allocator: std.mem.Allocator, app: *App, opts: Config.Agent) !*Agent
     try self.browser.init(app, .{}, null);
     errdefer self.browser.deinit();
 
-    self.session = try self.browser.newSession(notification);
-    self.session.cancel_hook = .{ .context = @ptrCast(self), .check = checkCancel };
+    try self.startSession();
 
     self.ai_client = if (llm) |l| try zenai.provider.Client.init(allocator, l, .{ .base_url = opts.base_url, .retry_policy = .long_running }) else null;
     errdefer if (self.ai_client) |c| c.deinit(allocator);
@@ -361,6 +360,13 @@ pub fn deinit(self: *Agent) void {
     self.allocator.destroy(self);
 }
 
+/// Create a fresh browser session and wire its cancel hook back to this agent
+/// so Ctrl-C aborts in-flight page work. Used at startup and by `/reset`.
+fn startSession(self: *Agent) !void {
+    self.session = try self.browser.newSession(self.notification);
+    self.session.cancel_hook = .{ .context = @ptrCast(self), .check = checkCancel };
+}
+
 // Tool definitions are compile-time constant; project them once per process.
 var global_tools_storage: [browser_tools.tool_defs.len]ProviderTool = undefined;
 var global_tools_once = std.once(initGlobalTools);
@@ -634,6 +640,8 @@ fn handleMeta(self: *Agent, arena: std.mem.Allocator, meta: *const SlashCommand.
         .verbosity => self.handleVerbosity(rest),
         .effort => self.handleEffort(rest),
         .usage => self.handleUsage(),
+        .clear => self.handleClear(),
+        .reset => self.handleReset(),
         .save => self.handleSave(arena, rest),
         .load => self.handleLoad(rest),
         .model => self.handleModel(arena, rest),
@@ -690,6 +698,34 @@ fn handleUsage(self: *Agent) void {
     }
 }
 
+/// Drop everything tied to the conversation: history (the system prompt
+/// re-seeds lazily on the next turn), cumulative usage, the recorded action
+/// buffer, and DOM node IDs. Shared by `/clear` and `/reset`.
+fn clearConversation(self: *Agent) void {
+    self.rollbackMessages(0);
+    self.save_buffer.reset();
+    self.total_usage = .{};
+    self.node_registry.reset();
+}
+
+/// Forget the conversation while leaving the browser session live — the loaded
+/// page stays put and cookies/logins are preserved.
+fn handleClear(self: *Agent) void {
+    self.clearConversation();
+    self.terminal.printInfo("Cleared conversation, usage, and node IDs. Page and cookies kept.", .{});
+}
+
+/// Full clean slate: everything `/clear` drops, plus a fresh browser session,
+/// so the loaded page, cookies, storage, and history are gone too.
+fn handleReset(self: *Agent) void {
+    self.startSession() catch |err| {
+        self.terminal.printError("reset failed: {s}", .{@errorName(err)});
+        return;
+    };
+    self.clearConversation();
+    self.terminal.printInfo("Reset conversation and browser session. Page, cookies, and storage cleared.", .{});
+}
+
 fn handleLoad(self: *Agent, rest: []const u8) void {
     const path = std.mem.trim(u8, rest, &std.ascii.whitespace);
     if (path.len == 0) {
@@ -1173,6 +1209,14 @@ fn printSlashHelp(self: *Agent, arena: std.mem.Allocator, target: []const u8) vo
                 "/usage — show cumulative token usage and cache hit rate for this session",
                 .{},
             ),
+            .clear => self.terminal.printInfo(
+                "/clear — forget the conversation (history, usage, recorded actions, node IDs); keeps the loaded page and cookies",
+                .{},
+            ),
+            .reset => self.terminal.printInfo(
+                "/reset — full reset: everything /clear does plus a new browser session, dropping the page, cookies, storage, and history",
+                .{},
+            ),
             .save => self.terminal.printInfo(
                 "/save [filename.js] [prompt] — save the session to [filename.js] (a random session-*.js if omitted). With an LLM, synthesizes an idiomatic script from the session and the optional prompt; with --no-llm, dumps the recorded actions verbatim.",
                 .{},

src/agent/SlashCommand.zig

@@ -47,7 +47,7 @@ pub const MetaCommand = struct {
 
     /// Dispatched by `Agent.handleMeta` via an exhaustive switch so adding
     /// a new meta command is a compile error until it's wired up there too.
-    const Tag = enum { help, quit, verbosity, effort, usage, save, load, model, provider };
+    const Tag = enum { help, quit, verbosity, effort, usage, clear, reset, save, load, model, provider };
 };
 
 pub const meta_commands = [_]MetaCommand{
@@ -56,6 +56,8 @@ pub const meta_commands = [_]MetaCommand{
     .{ .tag = .verbosity, .name = "verbosity", .hint = "<low|medium|high>", .values = &.{ "low", "medium", "high" }, .description = "Set agent verbosity" },
     .{ .tag = .effort, .name = "effort", .hint = "<none|minimal|low|medium|high|xhigh>", .values = &.{ "none", "minimal", "low", "medium", "high", "xhigh" }, .description = "Set per-turn reasoning effort" },
     .{ .tag = .usage, .name = "usage", .hint = "", .values = &.{}, .description = "Show token usage and cache stats for this session" },
+    .{ .tag = .clear, .name = "clear", .hint = "", .values = &.{}, .description = "Clear conversation history and usage (keeps page/cookies)" },
+    .{ .tag = .reset, .name = "reset", .hint = "", .values = &.{}, .description = "Reset conversation and browser session (drops page/cookies)" },
     .{ .tag = .save, .name = "save", .hint = "[filename.js] [prompt]", .values = &.{}, .description = "Save this session to a file" },
     .{ .tag = .load, .name = "load", .hint = "<path>", .values = &.{}, .description = "Load and run a script from disk" },
     .{ .tag = .model, .name = "model", .hint = "[name]", .values = &.{}, .description = "Change the model" },