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/resources.rs

@@ -1,3 +1,6 @@
+//! Compile-time embedded text resources: the system prompt, tool descriptions,
+//! and the in-app help screen shown on Ctrl+H.
+
 pub const SYSTEM_PROMPT: &str = include_str!("../src-misc/system-prompt.txt");
 pub const SYSTEM_TOOLS: &str = include_str!("../src-misc/system-tools.txt");