terminal: remove bare command validation

Stop highlighting bare tokens matching tool names as errors. Also
updates the zenai dependency.

build.zig.zon

@@ -39,8 +39,8 @@
             .hash = "N-V-__8AABGOuAC_dhAN07kfoP4dycCFi8Bka4O-tuhriNH8",
         },
         .zenai = .{
-            .url = "git+https://github.com/lightpanda-io/zenai.git#db96cffd3a9d0a7bbc26fc6caf99feb783abc164",
-            .hash = "zenai-0.0.0-iOY_VB_FAwB68e1j78QoLVTuyR0DCxAQwTWwADtZxkmV",
+            .url = "git+https://github.com/lightpanda-io/zenai.git#120f5fd2a2d29779fbc44584aaa472ad83c6a153",
+            .hash = "zenai-0.0.0-iOY_VP_EAwBATbpytTro7tmzT1aASeBvKPPvJEO2tEzB",
         },
         .isocline = .{
             .url = "git+https://github.com/arrufat/isocline.git#48d94027aec0408dc58af9ca2dfedf4720870e8c",

src/agent/Terminal.zig

@@ -556,13 +556,7 @@ fn highlighterCallback(henv: ?*c.ic_highlight_env_t, input: [*c]const u8, _: ?*a
         }
         highlightSlashArgs(henv, text, i);
     } else {
-        // A bare token whose first word matches a tool name suggests the user
-        // forgot the leading `/`. Flag it in error red.
-        if (closed and isKnownSlashName(cmd)) {
-            c.ic_highlight(henv, @intCast(cmd_start), @intCast(cmd.len), style_err.ptr);
-        }
-        // Natural-language prompts still benefit from `$LP_*` highlighting on
-        // any embedded env-var references.
+        // No leading `/`: a natural-language prompt, so no command validation.
         highlightDollarVars(henv, text, i);
     }
 }