deliver slash commands typed so the Claude TUI runs them

The composer routed everything through tmux paste-buffer -p (bracketed
paste), and Claude's TUI deliberately doesn't parse a leading slash on
pasted input — so /command and /skill arrived as literal text instead of
running. Now a recognised command (single-line, leading slash, token in
ClaudeConfig's slash list) is delivered via send-keys -l (typed) so the
TUI fires it; everything else keeps the bracketed-paste path, which also
leaves a stray leading slash (e.g. a /tmp path) as literal text rather
than mis-parsing it. The slash list is warmed lazily when a Claude pane
opens so custom commands are recognised.

T-153.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

test/builtin/claude/slash_commands_test.dart

@@ -0,0 +1,38 @@
+import 'package:clide/builtin/claude/src/slash_commands.dart';
+import 'package:test/test.dart';
+
+void main() {
+  group('slashCommandToken', () {
+    test('extracts the command word from single-line slash input', () {
+      expect(slashCommandToken('/model sonnet'), 'model');
+      expect(slashCommandToken('/whats-next'), 'whats-next');
+      expect(slashCommandToken('/foo\tbar'), 'foo');
+    });
+
+    test('returns null for non-command input', () {
+      expect(slashCommandToken('hello'), isNull);
+      expect(slashCommandToken(' /leading-space'), isNull);
+      expect(slashCommandToken('/'), isNull); // empty token
+      expect(slashCommandToken('/foo\nbar'), isNull); // multi-line
+    });
+  });
+
+  group('isKnownSlashCommand', () {
+    const known = {'model', 'clear', 'whats-next'};
+
+    test('true only when the token is a recognised command', () {
+      expect(isKnownSlashCommand('/model opus', known), isTrue);
+      expect(isKnownSlashCommand('/whats-next', known), isTrue);
+      expect(isKnownSlashCommand('/unknown-cmd', known), isFalse);
+    });
+
+    test('a path-like leading slash is not a command (stays literal)', () {
+      expect(isKnownSlashCommand('/tmp/foo.log has errors', known), isFalse);
+    });
+
+    test('non-slash and multi-line input is never a command', () {
+      expect(isKnownSlashCommand('hello world', known), isFalse);
+      expect(isKnownSlashCommand('/clear\nand more', {'clear'}), isFalse);
+    });
+  });
+}

test/builtin/claude/tmux_session_test.dart

@@ -124,4 +124,14 @@ void main() {
       ]);
     });
   });
+
+  group('sendCommand', () {
+    test('types the text literally (no bracketed paste) then submits Enter', () async {
+      await tmux.sendCommand('clide-claude-foo', '/whats-next');
+      expect(runner.calls, [
+        ['-L', 'clide', 'send-keys', '-t', 'clide-claude-foo', '-l', '--', '/whats-next'],
+        ['-L', 'clide', 'send-keys', '-t', 'clide-claude-foo', 'Enter'],
+      ]);
+    });
+  });
 }