Rename crate to escpos-vfd and add tokio support

Rename crate to escpos-vfd and add tokio support

Introduce a configurable crate-ready API with presets, typed errors,
optional Tokio async support, and expanded documentation.

taskfile.yml

@@ -5,6 +5,21 @@ vars:
   VFD_WIDTH: "20"
 
 tasks:
+  vfd:preset:
+    desc: Run minimal preset sync example
+    cmds:
+      - cargo run --example preset_sync -- {{.VFD_PORT}}
+
+  vfd:manual:
+    desc: Run minimal manual sync configuration example
+    cmds:
+      - cargo run --example manual_sync -- {{.VFD_PORT}}
+
+  vfd:tokio:
+    desc: Run Tokio worker example
+    cmds:
+      - cargo run --features tokio --example tokio_worker -- {{.VFD_PORT}} {{.VFD_WIDTH}}
+
   vfd:clock:
     desc: Run VFD clock example
     cmds:
@@ -18,7 +33,7 @@ tasks:
       - cargo run --example marquee -- {{.VFD_PORT}} {{.VFD_WIDTH}} {{.VFD_CPS | default "8"}} {{.VFD_END_PAUSE_MS | default "1500"}} {{.VFD_BRIGHTNESS | default "2"}}
     vars:
       VFD_CPS: "8"
-      VFD_END_PAUSE_MS: "1000"
+      VFD_END_PAUSE_MS: "1500"
       VFD_BRIGHTNESS: "3"
 
   vfd:brightness: