Log tabs with a daemon I/O view, and Playwright UI tests

The log view splits into All / Daemon I/O / Scans / HTTP. Daemon I/O is
the control protocol itself, logged where every command funnels through
so it covers socket clients, the CLI and the web UI alike. stderr and the
in-app buffer now have separate filters, so the UI can keep debug detail
the terminal should not carry.

Playwright drives a real browser against a daemon on fixture feeds. Eight
tests, each mapping to a bug that reached a user -- the Rust tests and the
stub-DOM smoke test cannot see a wrong selector or a dead handler.

It immediately found one: OPML folders rendered expanded by default,
because the code stored closed groups, so any folder never toggled counted
as open.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AdXho5tTkjFLeUXKbEjKBh

src/logbuf.rs

@@ -10,7 +10,7 @@ use tracing_subscriber::Layer;
 use tracing_subscriber::layer::Context;
 
 /// Kept small enough to be cheap to hold and to serialise in one response.
-const CAPACITY: usize = 2000;
+const CAPACITY: usize = 5000;
 
 #[derive(Clone, Debug, serde::Serialize)]
 pub struct LogLine {