quick wins (issues #9 #10 #11 #12 #13 #16) : am logs (tail+follow), am list --running/--sort, am config set, am alias add/remove/list, dedup historique, am open

src/commands/config_cmd.rs

@@ -5,6 +5,7 @@ use crate::cli::ConfigCmd;
 use crate::config;
 use crate::output::print_json;
 use anyhow::{anyhow, Context, Result};
+use clap::Parser;
 use std::path::{Path, PathBuf};
 use std::process::Command;
 
@@ -94,9 +95,63 @@ pub fn run(app: &App, cmd: &ConfigCmd) -> Result<i32> {
             Ok(status.code().unwrap_or(1))
         }
         ConfigCmd::Add { file } => add_file(app, file),
+        ConfigCmd::Set { key, value } => set_value(app, key, value),
     }
 }
 
+/// config set: set one dotted key (e.g. settings.default_shell) in the user
+/// configuration file, then validate the result.
+pub fn set_value(app: &App, key: &str, value: &str) -> Result<i32> {
+    let path = user_config_path(app)?;
+    let text = std::fs::read_to_string(&path)
+        .with_context(|| format!("cannot read {}", path.display()))?;
+    let mut root: serde_yaml::Value = serde_yaml::from_str(&text)
+        .with_context(|| format!("{} is not valid YAML", path.display()))?;
+
+    let parts: Vec<&str> = key.split('.').collect();
+    if parts.is_empty() || parts.iter().any(|p| p.is_empty()) {
+        return Err(anyhow!("invalid key '{key}' — expected a dotted path like settings.default_shell"));
+    }
+    let parsed = parse_scalar(value);
+    let mut node = root
+        .as_mapping_mut()
+        .ok_or_else(|| anyhow!("{} must contain a YAML mapping", path.display()))?;
+    for part in &parts[..parts.len() - 1] {
+        let entry = node
+            .entry(serde_yaml::Value::String(part.to_string()))
+            .or_insert_with(|| serde_yaml::Value::Mapping(Default::default()));
+        node = entry
+            .as_mapping_mut()
+            .ok_or_else(|| anyhow!("'{part}' is not a mapping — cannot descend into it"))?;
+    }
+    node.insert(
+        serde_yaml::Value::String(parts.last().unwrap().to_string()),
+        parsed,
+    );
+    std::fs::write(&path, serde_yaml::to_string(&root)?)
+        .with_context(|| format!("cannot write {}", path.display()))?;
+
+    // Validate the new configuration end to end.
+    let cli = crate::cli::Cli::parse_from(["am", "--config", path.to_str().unwrap_or_default()]);
+    config::load(&cli).map_err(|e| {
+        anyhow!("the new value makes the configuration invalid: {e:#}")
+    })?;
+    app.log.success(&format!("{key} = {value}"));
+    Ok(0)
+}
+
+/// Parse a scalar: booleans and integers keep their type, everything else
+/// stays a string.
+fn parse_scalar(value: &str) -> serde_yaml::Value {
+    if let Ok(b) = value.parse::<bool>() {
+        return serde_yaml::Value::Bool(b);
+    }
+    if let Ok(i) = value.parse::<i64>() {
+        return serde_yaml::Value::Number(i.into());
+    }
+    serde_yaml::Value::String(value.to_string())
+}
+
 fn user_config_path_if_any(app: &App) -> Option<PathBuf> {
     app.paths
         .config_dir