Three bugs fixed:
- No tokio reactor: glib::spawn_future_local does not provide a
tokio context, so reqwest/hyper panicked at runtime. Introduce
src/runtime.rs with a multi-thread tokio Runtime (init() called
from main before the GTK app starts). runtime::spawn() posts the
async result back to GTK via a tokio oneshot channel awaited by
glib::spawn_future_local, which only polls a flag (no I/O).
runtime::spawn_bg() is used for fire-and-forget background calls.
- Enter key didn't submit login: connect_apply on AdwEntryRow only
fires when show-apply-button is true. Switch to connect_entry_activated
which fires on Return in all three login rows.
- Wrong API URL: the app constructed /accounts/ClientLogin directly
off the server host, yielding a 404. Add normalize_base_url() in
api.rs that appends /api/greader.php when the URL doesn't already
contain it, so users can enter just https://rss.example.com.
