feat: add IRONCLAW_BASE_DIR env var with LazyLock caching (#397)

src/tools/builtin/job.rs

@@ -14,6 +14,7 @@ use async_trait::async_trait;
 use chrono::Utc;
 use uuid::Uuid;
 
+use crate::bootstrap::ironclaw_base_dir;
 use crate::channels::IncomingMessage;
 use crate::channels::web::types::SseEvent;
 use crate::context::{ContextManager, JobContext, JobState};
@@ -554,10 +555,7 @@ fn validate_env_var_name(name: &str) -> Result<(), ToolError> {
 }
 
 fn projects_base() -> PathBuf {
-    dirs::home_dir()
-        .unwrap_or_else(|| PathBuf::from("."))
-        .join(".ironclaw")
-        .join("projects")
+    ironclaw_base_dir().join("projects")
 }
 
 /// Resolve the project directory, creating it if it doesn't exist.

src/tools/builtin/message.rs

@@ -8,6 +8,7 @@ use std::sync::Arc;
 use async_trait::async_trait;
 use tokio::sync::RwLock;
 
+use crate::bootstrap::ironclaw_base_dir;
 use crate::channels::{ChannelManager, OutgoingResponse};
 use crate::context::JobContext;
 use crate::tools::tool::{
@@ -27,9 +28,7 @@ pub struct MessageTool {
 
 impl MessageTool {
     pub fn new(channel_manager: Arc<ChannelManager>) -> Self {
-        let base_dir = dirs::home_dir()
-            .unwrap_or_else(|| std::path::PathBuf::from("."))
-            .join(".ironclaw");
+        let base_dir = ironclaw_base_dir();
 
         Self {
             channel_manager,

src/tools/mcp/config.rs

@@ -9,6 +9,7 @@ use std::path::{Path, PathBuf};
 use serde::{Deserialize, Serialize};
 use tokio::fs;
 
+use crate::bootstrap::ironclaw_base_dir;
 use crate::tools::tool::ToolError;
 
 /// Configuration for connecting to a remote MCP server.
@@ -251,10 +252,7 @@ impl From<ConfigError> for ToolError {
 
 /// Get the default MCP servers configuration path.
 pub fn default_config_path() -> PathBuf {
-    dirs::home_dir()
-        .unwrap_or_else(|| PathBuf::from("."))
-        .join(".ironclaw")
-        .join("mcp-servers.json")
+    ironclaw_base_dir().join("mcp-servers.json")
 }
 
 /// Load MCP server configurations from the default location.