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/controller/command.rs

@@ -1,5 +1,9 @@
+//! Slash-command parser that maps TUI `/foo` input lines into `Command`
+//! variants for the action dispatch system.
+
 use crate::app::mode::ModeKind;
 
+/// A parsed slash command from the TUI input buffer.
 #[derive(Debug, Clone, PartialEq)]
 pub enum Command {
     Help,
@@ -23,6 +27,14 @@ pub enum Command {
     Unknown(String),
 }
 
+/// Parse a slash-prefixed input line into a `Command` value.
+///
+/// Flow: trim -> check for leading `/` -> split on space (max 3 parts) ->
+/// match the first token against known commands -> extract arguments from
+/// the remaining parts.
+///
+/// Why: early return `Unknown` for non-slash lines so the caller can treat
+/// them as regular chat input.
 pub fn parse_command(text: &str) -> Command {
     let text = text.trim();
     if !text.starts_with('/') {