Refactor CLI, add refresh command, fix port detection, add device tracking

- Remove build/upload/monitor subcommands (projects are self-contained)
- Remove ctrlc dependency (only used by removed monitor watch mode)
- Update next-steps messaging to reference project scripts directly

- Add 'anvil refresh [DIR] [--force]' to update project scripts
  to latest templates without touching user code

- Fix Windows port detection: replace fragile findstr/batch TOML
  parsing with proper comment-skipping logic; add _detect_port.ps1
  helper for reliable JSON-based port detection via PowerShell

- Add .anvil.local for machine-specific config (gitignored)
  - 'anvil devices --set [PORT] [-d DIR]' saves port + VID:PID
  - 'anvil devices --get [-d DIR]' shows saved port status
  - VID:PID tracks USB devices across COM port reassignment
  - Port resolution: -p flag > VID:PID > saved port > auto-detect
  - Uppercase normalization for Windows COM port names

- Update all .bat/.sh templates to read from .anvil.local
- Remove port entries from .anvil.toml (no machine-specific config in git)
- Add .anvil.local to .gitignore template
- Expand 'anvil devices' output with VID:PID, serial number, and
  usage instructions

src/project/config.rs

@@ -31,6 +31,8 @@ pub struct BuildConfig {
 #[derive(Debug, Serialize, Deserialize, Clone)]
 pub struct MonitorConfig {
     pub baud: u32,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub port: Option<String>,
 }
 
 impl ProjectConfig {
@@ -49,6 +51,7 @@ impl ProjectConfig {
             },
             monitor: MonitorConfig {
                 baud: 115200,
+                port: None,
             },
         }
     }
@@ -143,13 +146,6 @@ pub fn anvil_home() -> Result<PathBuf> {
     Ok(anvil_dir)
 }
 
-/// Return the build cache directory (~/.anvil/builds).
-pub fn build_cache_dir() -> Result<PathBuf> {
-    let dir = anvil_home()?.join("builds");
-    fs::create_dir_all(&dir)?;
-    Ok(dir)
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -223,4 +219,4 @@ mod tests {
         assert!(flags.contains("-Werror"));
         assert!(flags.contains("-I"));
     }
-}
+}