Show exec output on success with trimmed display (#4113)

- Refactor Exec Cell into its own module
- update exec command rendering to inline the first command line
- limit continuation lines
- always show trimmed output

codex-rs/tui/src/snapshots/codex_tui__history_cell__tests__multiline_command_both_lines_wrap_with_correct_prefixes.snap

@@ -1,10 +1,8 @@
 ---
 source: tui/src/history_cell.rs
-assertion_line: 1942
 expression: rendered
 ---
-• Ran
-  └ first_token_is_long_enou
-        gh_to_wrap
-    second_token_is_also_lon
-        g_enough_to_wrap
+• Ran first_token_is_long_en
+  │ ough_to_wrap
+  │ second_token_is_also_lon
+  │ … +1 lines

codex-rs/tui/src/snapshots/codex_tui__history_cell__tests__multiline_command_without_wrap_uses_branch_then_eight_spaces.snap

@@ -2,6 +2,5 @@
 source: tui/src/history_cell.rs
 expression: rendered
 ---
-• Ran
-  └ echo one
-    echo two
+• Ran echo one
+  │ echo two

codex-rs/tui/src/snapshots/codex_tui__history_cell__tests__multiline_command_wraps_with_extra_indent_on_subsequent_lines.snap

@@ -1,10 +1,7 @@
 ---
 source: tui/src/history_cell.rs
-assertion_line: 1797
 expression: rendered
 ---
-• Ran
-  └ set -o pipefail
-    cargo test
-        --all-features
-        --quiet
+• Ran set -o pipefail
+  │ cargo test
+  │ --all-features --quiet

codex-rs/tui/src/snapshots/codex_tui__history_cell__tests__ran_cell_multiline_with_stderr_snapshot.snap

@@ -2,13 +2,11 @@
 source: tui/src/history_cell.rs
 expression: rendered
 ---
-• Ran
-  └ echo
-        this_is_a_very_long_
-        single_token_that_wi
-        ll_wrap_across_the_a
-        vailable_width
-    error: first line on
+• Ran echo
+  │ this_is_a_very_long_si
+  │ ngle_token_that_will_w
+  │ … +2 lines
+  └ error: first line on
     stderr
     error: second line on
     stderr

codex-rs/tui/src/snapshots/codex_tui__history_cell__tests__single_line_command_wraps_with_four_space_continuation.snap

@@ -1,9 +1,7 @@
 ---
 source: tui/src/history_cell.rs
-assertion_line: 1869
 expression: rendered
 ---
-• Ran
-  └ a_very_long_token_wi
-        thout_spaces_to_
-        force_wrapping
+• Ran a_very_long_token_
+  │ without_spaces_to_
+  │ force_wrapping

codex-rs/tui/src/snapshots/codex_tui__history_cell__tests__stderr_tail_more_than_five_lines_snapshot.snap

@@ -5,11 +5,6 @@ expression: rendered
 • Ran seq 1 10 1>&2 && false
   └ 1
     2
-    3
-    4
-    5
-    6
-    7
-    8
+    … +6 lines
     9
     10