tui: remove debug/test-only crate features (#16457)

## Why

The remaining `vt100-tests` and `debug-logs` features in `codex-tui`
were only gating test-only and debug-only behavior. Those feature
toggles add Cargo and Bazel permutations without buying anything, and
they make it easier for more crate features to linger in the workspace.

## What changed

- delete `vt100-tests` and `debug-logs` from `codex-tui`
- always compile the VT100 integration tests in the TUI test target
instead of hiding them behind a Cargo feature
- remove the unused textarea debug logging branch instead of replacing
it with another gate
- add the required argument-comment annotations in the VT100 tests now
that Bazel sees those callsites during linting
- shrink the manifest verifier allowlist again so only the remaining
real feature exceptions stay permitted

## How tested

- `cargo test -p codex-tui`
- `just argument-comment-lint -p codex-tui`

codex-rs/tui/tests/suite/vt100_live_commit.rs

@@ -1,21 +1,21 @@
-#![cfg(feature = "vt100-tests")]
-
 use crate::test_backend::VT100Backend;
 use ratatui::layout::Rect;
 use ratatui::text::Line;
 
 #[test]
 fn live_001_commit_on_overflow() {
-    let backend = VT100Backend::new(20, 6);
+    let backend = VT100Backend::new(/*width*/ 20, /*height*/ 6);
     let mut term = match codex_tui::custom_terminal::Terminal::with_options(backend) {
         Ok(t) => t,
         Err(e) => panic!("failed to construct terminal: {e}"),
     };
-    let area = Rect::new(0, 5, 20, 1);
+    let area = Rect::new(
+        /*x*/ 0, /*y*/ 5, /*width*/ 20, /*height*/ 1,
+    );
     term.set_viewport_area(area);
 
     // Build 5 explicit rows at width 20.
-    let mut rb = codex_tui::live_wrap::RowBuilder::new(20);
+    let mut rb = codex_tui::live_wrap::RowBuilder::new(/*target_width*/ 20);
     rb.push_fragment("one\n");
     rb.push_fragment("two\n");
     rb.push_fragment("three\n");
@@ -23,7 +23,7 @@ fn live_001_commit_on_overflow() {
     rb.push_fragment("five\n");
 
     // Keep the last 3 in the live ring; commit the first 2.
-    let commit_rows = rb.drain_commit_ready(3);
+    let commit_rows = rb.drain_commit_ready(/*max_keep*/ 3);
     let lines: Vec<Line<'static>> = commit_rows.into_iter().map(|r| r.text.into()).collect();
 
     codex_tui::insert_history::insert_history_lines(&mut term, lines)