Enhance tool documentation and add new features

- Added module-level documentation for memory tools (`remember`, `recall`, `forget`) to clarify their purpose.
- Improved documentation in `recall.rs` and `remember.rs` to describe the functionality and flow of memory entry operations.
- Updated `mod.rs` to include descriptions for the tool trait and execution context.
- Enhanced `plan.rs` with detailed comments on plan-mode signaling tools.
- Documented text search tools in `search.rs` to explain their functionality.
- Improved sequential-thinking tool documentation in `seqthink.rs`.
- Added safety filter documentation in `shell_filter` for credential and git operations.
- Enhanced utility tools documentation, including `cd`, `dir_cache_update`, and `todowrite`.
- Improved rendering documentation in view modules (`chat`, `markdown`, `status`, `workflow`) to clarify rendering flows and purposes.

src/app/subagent/spawn.rs

@@ -1,5 +1,10 @@
+//! AgentDefinition -- declarative specification for instantiating a
+//! subagent from workflow scripts or programmatic calls.
+
 use serde::{Deserialize, Serialize};
 
+/// Declarative specification for instantiating a subagent: name, role,
+/// optional system prompt, allowed tools, step budget, and temperature.
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct AgentDefinition {
     pub name: String,
@@ -11,6 +16,8 @@ pub struct AgentDefinition {
 }
 
 impl AgentDefinition {
+    /// Create an agent definition with the required name and role; all
+    /// optional fields start as `None`.
     pub fn new(name: String, role: String) -> Self {
         AgentDefinition {
             name,
@@ -22,6 +29,7 @@ impl AgentDefinition {
         }
     }
 
+    /// Builder method: limit this agent to at most `steps` LLM calls.
     pub fn with_max_steps(mut self, steps: usize) -> Self {
         self.max_steps = Some(steps);
         self