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-iam/src/application/session_service.rs

@@ -1,9 +1,22 @@
 //! Session management use-cases.
 //!
-//! `SessionServiceImpl` implements `SessionService` by delegating to
+//! `SessionServiceImpl` implements [`SessionService`] by delegating to
 //! injected repository implementations, keeping the orchestration logic
 //! independent of any concrete persistence mechanism.
+//!
+//! # Flow
+//!
+//! - **`create_session`** — generates a UUID v4 id, creates a `Session` entity,
+//!   delegates persistence to `SessionRepository`.
+//! - **`list_all`** — delegates to `SessionRepository::list_sessions`.
+//! - **`archive_session`** — loads session, sets `archived = true`, persists.
+//!
+//! # Components
+//!
+//! - `SessionServiceImpl<R, L>` — service over two generic repositories
+//! - `new` / `create_session` / `list_all` / `archive_session` — lifecycle ops
 use std::path::PathBuf;
+use tracing;
 
 use uuid::Uuid;
 
@@ -13,8 +26,11 @@ use crate::domain::session::Session;
 
 /// Concrete session service backed by generic repository implementations.
 pub struct SessionServiceImpl<R: SessionRepository, L: SessionLockRepository> {
+    /// Repository for session CRUD operations.
     pub session_repo: R,
+    /// Repository for session lock acquire/release.
     pub lock_repo: L,
+    /// Base data directory passed to repository methods.
     pub base_dir: PathBuf,
 }
 
@@ -39,15 +55,18 @@ impl<R: SessionRepository, L: SessionLockRepository> SessionService for SessionS
             title.to_string()
         };
         let session = Session::new(id, title_owned);
+        tracing::debug!(session_id = %session.id, title = %session.title, "creating new session");
         self.session_repo.save_session(&self.base_dir, &session)?;
         Ok(session)
     }
 
     fn list_all(&self) -> anyhow::Result<Vec<Session>> {
+        tracing::debug!("listing all sessions");
         self.session_repo.list_sessions(&self.base_dir)
     }
 
     fn archive_session(&self, id: &str) -> anyhow::Result<()> {
+        tracing::debug!(session_id = %id, "archiving session");
         let mut session = self.session_repo.load_session(&self.base_dir, id)?;
         session.archived = true;
         session.updated_at = std::time::SystemTime::now()