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/tool/git_operator.rs

@@ -1,9 +1,12 @@
+//! Generic tool for running arbitrary git subcommands.
+
 use std::process::Command;
 use serde_json::{json, Value};
 use anyhow::{Result, anyhow};
 use super::Tool;
 use super::ToolCtx;
 
+/// Tool that runs `git <operation> [args...]` and returns combined stdout/stderr.
 pub struct GitOperator;
 
 impl Tool for GitOperator {
@@ -33,6 +36,16 @@ impl Tool for GitOperator {
         })
     }
 
+    /// Run `git <operation> [args...]` and return its combined output.
+    ///
+    /// Flow: extract `operation` + `args` → spawn `git <operation> <args>` → trim and
+    ///       join stdout/stderr.
+    ///
+    /// Why: no allowlist here — the model may run any git subcommand; destructive
+    /// operations are blocked upstream by `shell_filter::git`, not by this tool.
+    ///
+    /// Return: trimmed combined output on success; error including exit code and
+    /// stderr on failure.
     fn run(&self, _ctx: &ToolCtx, args: &Value) -> Result<String> {
         let operation = args.get("operation")
             .and_then(|v| v.as_str())