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/app/runtime/context/squash.rs

@@ -1,4 +1,3 @@
-#![allow(dead_code)]
 //! Per-tool-result compression: shrink large tool outputs before they
 //! ever enter conversation history, dispatching by content shape.
 //!
@@ -12,6 +11,7 @@
 //! overall budget.
 use std::collections::HashSet;
 use std::fmt::Write;
+use tracing;
 
 /// Below this size, compression isn't worth the risk of losing detail —
 /// pass the output through unchanged.
@@ -46,16 +46,28 @@ const LOG_SHAPED_TOOLS: &[&str] = &["bash"];
 /// Return: `output` unchanged if `tool_name` is in `NEVER_SQUASH` or at
 /// or under `SQUASH_FLOOR_BYTES`; otherwise the compressed form from
 /// whichever detector matches its content shape.
+///
+/// # Status
+///
+/// Defined but not yet wired into the tool-execution pipeline; will be
+/// called from `tool::shell` and MCP result handlers once integration
+/// is complete.
+#[expect(dead_code, reason = "will be wired into the tool-execution pipeline")]
 pub fn apply(tool_name: &str, output: &str) -> String {
+    tracing::trace!(tool_name, output_len = output.len(), "squash::apply — start");
     if NEVER_SQUASH.contains(&tool_name) || output.len() <= SQUASH_FLOOR_BYTES {
+        tracing::trace!(tool_name, "squash::apply — passthrough (never-squash tool or under floor)");
         return output.to_string();
     }
     if serde_json::from_str::<serde_json::Value>(output).is_ok() {
+        tracing::trace!(tool_name, "squash::apply — routing to squash_json");
         return squash_json(output);
     }
     if LOG_SHAPED_TOOLS.contains(&tool_name) && looks_log_shaped(output) {
+        tracing::trace!(tool_name, "squash::apply — routing to squash_log");
         return squash_log(output);
     }
+    tracing::trace!(tool_name, "squash::apply — routing to squash_generic");
     squash_generic(output, GENERIC_BUDGET_BYTES)
 }
 
@@ -287,6 +299,16 @@ fn squash_generic(text: &str, budget: usize) -> String {
 
 /// Render a subset of `lines` in order, inserting a `[N lines omitted]`
 /// marker at every gap between kept lines.
+///
+/// Flow: sort kept indices → iterate; for each kept line, if a gap
+/// exists before it write `[N lines omitted]`, then write the line.
+/// After all kept lines, write a final omission marker if lines remain.
+///
+/// Why `[N lines omitted]` instead of a comment-shaped marker: the
+/// `rtk` project's own regression tests found that comment shapes get
+/// parsed by the LLM as code and trigger a retry loop.
+///
+/// Return: rendered string with kept lines in original order.
 fn render_kept_lines(lines: &[&str], keep: &HashSet<usize>) -> String {
     let mut kept_sorted: Vec<usize> = keep.iter().copied().collect();
     kept_sorted.sort_unstable();
@@ -309,6 +331,9 @@ fn render_kept_lines(lines: &[&str], keep: &HashSet<usize>) -> String {
 
 #[cfg(test)]
 mod tests {
+    //! Unit tests for tool-result squashing: floor threshold, read-tool
+    //! exemption, JSON structure preservation, log compression, and
+    //! generic truncation with head/tail retention.
     use super::*;
 
     #[test]