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/view/chat.rs

@@ -20,6 +20,7 @@ use ratatui::style::{Color, Modifier, Style};
 use ratatui::text::{Line, Span};
 use ratatui::widgets::{Block, BorderType, Borders, Paragraph};
 use ratatui::Frame;
+use tracing;
 
 /// Column width reserved for the `{role} {time}  ` header prefix; wrapped
 /// continuation lines and Tool sub-lines indent to this width so content
@@ -101,7 +102,19 @@ fn needs_speaker_separator(_prev_role: Option<&Role>, _role: &Role) -> bool {
 }
 
 /// Render the scrollable chat transcript panel in tight inline-log style.
+///
+/// Flow: iterate transcript messages → render each into styled `Line`s
+/// with a compact `{role} {time}` header prefix → append streaming
+/// spinner if a turn is in flight → slice to the visible scroll window
+/// → wrap in a bordered Paragraph widget.
 pub fn draw_chat(frame: &mut Frame, area: Rect, state: &crate::app::state::rest::AppStateRest) {
+    let msg_count = state.transcript_cache.messages.len();
+    tracing::debug!(
+        msg_count,
+        area = %format!("{}x{}", area.width, area.height),
+        scroll_offset = state.scroll.offset,
+        "draw_chat rendering transcript"
+    );
     let messages = &state.transcript_cache.messages;
     let scroll_offset = state.scroll.offset;
     let max_visible = (area.height as usize).saturating_sub(3);