Refactor IPC and DTO structures; remove unused code and streamline message handling

- Removed unused structs and methods from `response.rs`, `usage.rs`, and `client.rs`.
- Simplified `Connection` handling in `conn.rs` to only support Unix sockets.
- Updated `IpcServer` to exclusively use Unix sockets and removed TCP handling.
- Cleaned up `editlog.rs` by removing loading and recent entry methods.
- Refactored `memory.rs` to eliminate unused functions related to lesson promotion and retrospective creation.
- Enhanced `search.rs` to support multiple search providers and improved error handling.
- Updated chat view logic to simplify message display and improve user experience.
- Removed deprecated modules and constants from various files to streamline the codebase.

src/tool/workflow.rs

@@ -11,7 +11,7 @@ impl Tool for WorkflowRun {
     }
 
     fn description(&self) -> &'static str {
-        "Execute a workflow script by delegating to the workflow engine"
+        "Execute a workflow script that can spawn multiple subagents in parallel, pipeline, or phased stages. Use when a task benefits from decomposition into independent subtasks. Simple tasks should be handled inline without this tool."
     }
 
     fn parameters(&self) -> Value {
@@ -20,11 +20,11 @@ impl Tool for WorkflowRun {
             "properties": {
                 "script": {
                     "type": "string",
-                    "description": "Workflow script content or path to a workflow file"
+                    "description": "JSON-encoded workflow script with name, description, script (Agent/Parallel/Pipeline/Phase primitives), and options (max_concurrency, continue_on_error)"
                 },
                 "args": {
                     "type": "object",
-                    "description": "Optional arguments passed to the workflow script"
+                    "description": "Optional string key-value arguments passed to the workflow script for template substitution ({{key}} placeholders)"
                 }
             },
             "required": ["script"]
@@ -52,3 +52,37 @@ impl Tool for WorkflowRun {
         crate::app::workflow::engine::run_workflow(&workflow_script, &workflow_args)
     }
 }
+
+pub struct NoteFinding;
+
+impl Tool for NoteFinding {
+    fn name(&self) -> &'static str {
+        "note_finding"
+    }
+
+    fn description(&self) -> &'static str {
+        "Share a finding with sibling agents in the same workflow_run. Findings are ephemeral to the current run and will be prepended to other agents' next tool-round context. Does not persist to memory."
+    }
+
+    fn parameters(&self) -> Value {
+        json!({
+            "type": "object",
+            "properties": {
+                "text": {
+                    "type": "string",
+                    "description": "The finding to share with sibling agents"
+                }
+            },
+            "required": ["text"]
+        })
+    }
+
+    fn run(&self, _ctx: &ToolCtx, args: &Value) -> Result<String> {
+        let text = args.get("text")
+            .and_then(|v| v.as_str())
+            .ok_or_else(|| anyhow!("missing required argument: text"))?;
+
+        crate::app::workflow::engine::note_finding(text);
+        Ok(format!("finding recorded: {}", text.chars().take(80).collect::<String>()))
+    }
+}