Improve error warnings and command behavior for vmic

- Updated `vmic route` to use "none" instead of "off" for source removal, standardizing terminology.
- Added warnings for handling stale `pw-loopback` processes during `vmic edit` operations.
- Enhanced logging for `vmic route` to provide detailed feedback on moved streams.
- Ensured stable sorting of ports in PipeWire graph for consistent behavior.

src/cli.rs

@@ -60,8 +60,8 @@ pub struct RouteArgs {
     #[arg(short, long = "output", value_name = "APP[:MEDIA]")]
     pub outputs: Vec<String>,
 
-    /// Mix a hardware source into the vmic, or "off" to remove it.
-    #[arg(short, long = "source", value_name = "SOURCE|off")]
+    /// Mix a hardware source into the vmic, or "none" to remove it.
+    #[arg(short, long = "source", value_name = "SOURCE|none")]
     pub source: Option<String>,
 }