fix(cli): improve enter/stop error context

- Stop now takes the store lock like other mutating commands\n- Wrap enter/exec/stop errors with env input and resolved id context\n- Enter/exec now return a clearer error when the env is already running or not built

crates/karapace-cli/src/commands/enter.rs

@@ -13,10 +13,15 @@ pub fn run(
     let _lock = StoreLock::acquire(&layout.lock_file()).map_err(|e| format!("store lock: {e}"))?;
 
     let resolved = resolve_env_id_pretty(engine, env_id)?;
+    let short = resolved.get(..12).unwrap_or(&resolved);
     if command.is_empty() {
-        engine.enter(&resolved).map_err(|e| e.to_string())?;
+        engine
+            .enter(&resolved)
+            .map_err(|e| format!("{e} (env '{env_id}' -> {short})"))?;
     } else {
-        engine.exec(&resolved, command).map_err(|e| e.to_string())?;
+        engine
+            .exec(&resolved, command)
+            .map_err(|e| format!("{e} (env '{env_id}' -> {short})"))?;
     }
     Ok(EXIT_SUCCESS)
 }

crates/karapace-cli/src/commands/exec.rs

@@ -14,6 +14,9 @@ pub fn run(
     let _lock = StoreLock::acquire(&layout.lock_file()).map_err(|e| format!("store lock: {e}"))?;
 
     let resolved = resolve_env_id_pretty(engine, env_id)?;
-    engine.exec(&resolved, command).map_err(|e| e.to_string())?;
+    let short = resolved.get(..12).unwrap_or(&resolved);
+    engine
+        .exec(&resolved, command)
+        .map_err(|e| format!("{e} (env '{env_id}' -> {short})"))?;
     Ok(EXIT_SUCCESS)
 }

crates/karapace-cli/src/commands/stop.rs

@@ -1,10 +1,17 @@
 use super::{resolve_env_id_pretty, EXIT_SUCCESS};
-use karapace_core::Engine;
+use karapace_core::{Engine, StoreLock};
+use karapace_store::StoreLayout;
 use std::path::Path;
 
-pub fn run(engine: &Engine, _store_path: &Path, env_id: &str) -> Result<u8, String> {
+pub fn run(engine: &Engine, store_path: &Path, env_id: &str) -> Result<u8, String> {
+    let layout = StoreLayout::new(store_path);
+    let _lock = StoreLock::acquire(&layout.lock_file()).map_err(|e| format!("store lock: {e}"))?;
+
     let resolved = resolve_env_id_pretty(engine, env_id)?;
-    engine.stop(&resolved).map_err(|e| e.to_string())?;
-    println!("stopped environment {env_id}");
+    let short = resolved.get(..12).unwrap_or(&resolved);
+    engine
+        .stop(&resolved)
+        .map_err(|e| format!("{e} (env '{env_id}' -> {short})"))?;
+    println!("stopped environment {env_id} ({short})");
     Ok(EXIT_SUCCESS)
 }

crates/karapace-core/src/engine.rs

@@ -378,7 +378,17 @@ impl Engine {
             .get(env_id)
             .map_err(|_| CoreError::EnvNotFound(env_id.to_owned()))?;
 
-        validate_transition(meta.state, EnvState::Running)?;
+        if meta.state == EnvState::Running {
+            return Err(CoreError::Runtime(
+                karapace_runtime::RuntimeError::AlreadyRunning(env_id.to_owned()),
+            ));
+        }
+        if meta.state != EnvState::Built {
+            return Err(CoreError::InvalidTransition {
+                from: meta.state.to_string(),
+                to: "enter requires built state".to_owned(),
+            });
+        }
 
         let normalized = self.load_manifest(&meta.manifest_hash)?;
         let store_str = self.store_root_str.clone();
@@ -415,7 +425,17 @@ impl Engine {
             .get(env_id)
             .map_err(|_| CoreError::EnvNotFound(env_id.to_owned()))?;
 
-        validate_transition(meta.state, EnvState::Running)?;
+        if meta.state == EnvState::Running {
+            return Err(CoreError::Runtime(
+                karapace_runtime::RuntimeError::AlreadyRunning(env_id.to_owned()),
+            ));
+        }
+        if meta.state != EnvState::Built {
+            return Err(CoreError::InvalidTransition {
+                from: meta.state.to_string(),
+                to: "exec requires built state".to_owned(),
+            });
+        }
 
         let normalized = self.load_manifest(&meta.manifest_hash)?;
         let store_str = self.store_root_str.clone();