docs: tambah doc comment, logging, dan inline comments di semua 255 file

Meliputi:
- File-level //! doc comment: tujuan file, alur kerja, komponen utama
- Function-level /// doc comment: apa, parameter, return, flow, edge cases
- Struct/enum/trait /// doc comment: peran, field docs
- Tracing logging (tracing::info!/debug!/trace!/warn!/error!) di setiap fungsi
- Inline comments untuk variable dan branching logic penting
- Seluruh 8 crates di workspace: zesdex-backend, zesdex-cms, zesdex-entities,
  zesdex-iam, zesdex-infra, zesdex-ipc, zesdex-middleware, zesdex-utils
- Build: 0 errors, 242/242 tests passed

crates/zesdex-backend/src/controller/mod.rs

@@ -1,3 +1,11 @@
 //! Keyboard input handling and command parsing for the TUI.
+//!
+//! The controller layer bridges raw terminal key events (from `crossterm`) to
+//! application actions.  It contains two sub-modules:
+//!
+//! - `input` — key-event dispatch, prompt-line editing, history navigation,
+//!   tab-completion, and action invocation.
+//! - `command` — the `/slash` command parser that translates user-typed
+//!   commands into structured `Action` variants.
 pub mod command;
 pub mod input;