feat(log): live verbosity toggle — dock Level chip + clide log level (T-433)

The boot-time toggle (CLIDE_LOG / app.log.level) existed; this makes it
adjustable at runtime, from the two surfaces that fit — D-6 parity — and NOT a
Claude-composer slash command (log verbosity isn't a Claude-session concept).

- Output dock Level chip: was a view-only filter; now also drives the kernel
  Logger.minLevel and persists app.log.level, so the choice is real (changes
  what's captured) and survives restart. Initialized from the logger's current
  level so it reflects a CLI change. A null callback keeps it a pure view
  filter (tests / no kernel).
- `clide log level [<level>]` (lib/src/daemon/log_commands.dart): no arg reports
  the level + vocabulary; a valid level sets the live logger and persists;
  unknown → bad_arg (code 64), logger untouched. Wired in buildDispatcher with
  the kernel logger + settings (captured post-boot).

Tested: the command (get/set/case-insensitive/bad-arg, live + persist) and the
controller (initial level, callback fires, same-level no-op, filter-only when
unwired). Coverage gate 95.05%.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/src/daemon/log_commands.dart

@@ -0,0 +1,37 @@
+/// Registers `log.level` — the live dev/prod verbosity toggle (T-433).
+///
+/// With no arg it reports the running [Logger]'s minimum level; with
+/// `level=<name>` it sets the Logger AND persists `app.log.level` so the
+/// choice survives a restart (resolved at boot by `resolveLogLevel`). The UI
+/// half is the output dock's Level chip — D-6 parity. Flutter-free + trivially
+/// testable: the handler takes the Logger and a persist callback.
+library;
+
+import 'package:clide/kernel/src/log.dart';
+
+import '../ipc/envelope.dart';
+import 'dispatcher.dart';
+
+/// Persists the chosen level name (the owner wires this to
+/// `settings.set('app.log.level', name)`).
+typedef LogLevelPersist = Future<void> Function(String levelName);
+
+void registerLogCommands(DaemonDispatcher d, Logger log, LogLevelPersist persist) {
+  d.register('log.level', (req) async {
+    final raw = req.args['level'];
+    if (raw == null) {
+      // Read: report the current level + the vocabulary.
+      return IpcResponse.ok(id: req.id, data: {'level': log.minLevel.name, 'levels': LogLevel.values.map((l) => l.name).toList()});
+    }
+    final level = parseLogLevel(raw is String ? raw : raw.toString());
+    if (level == null) {
+      return IpcResponse.err(
+        id: req.id,
+        error: IpcError(code: 64, kind: 'bad_arg', message: 'unknown log level: $raw', hint: 'one of: ${LogLevel.values.map((l) => l.name).join(', ')}'),
+      );
+    }
+    log.minLevel = level;
+    await persist(level.name);
+    return IpcResponse.ok(id: req.id, data: {'level': level.name});
+  });
+}