fix(gui,cli): count what a folder's first scan has checked (#46)

The first pass over a synced folder has no baseline to estimate from, so
its scan showed only "checking for changes…" in the app and "scanning…"
in `pdfs sync list`. For a large folder that scan reads every item on
Proton Drive before anything downloads, which takes many minutes and
looked stuck. Both now show how many items the scan has checked so far.

crates/pdfs-cli/src/main.rs

@@ -1143,7 +1143,14 @@ fn cmd_sync(action: SyncCmd) -> Result<()> {
                         // A pass in flight says what it is doing, indented under it.
                         if let Some(p) = &f.progress {
                             match p.phase {
-                                SyncPhase::Scanning if p.total == 0 => println!("      scanning…"),
+                                SyncPhase::Scanning if p.total == 0 && p.done == 0 => {
+                                    println!("      scanning…")
+                                }
+                                // A first pass has no estimate yet; the count alone
+                                // shows a long first scan is moving.
+                                SyncPhase::Scanning if p.total == 0 => {
+                                    println!("      scanning: {} checked", p.done)
+                                }
                                 SyncPhase::Scanning => {
                                     println!(
                                         "      scanning: {} of {}",