feat(cli): add Unicode width support for input composer

[titan]

Summary by cubic

Adds proper Unicode display width handling and horizontal scrolling to the CLI input composer, fixing misaligned cursors with CJK and emoji. Also simplifies key handling across pickers for clearer behavior.

• New Features

  • Use unicode-width to compute display width (CJK=2, ASCII=1, zero-width=0).
  • Composer windows input to available columns and keeps the cursor visible; shows "… " when the start is truncated, otherwise "❯ ".
  • Width calculation accounts for borders to prevent overflow.

• Refactors

  • Simplified Up/Down/Esc handling using match guards across palette, model/provider/branch/session pickers, and onboarding connect menu.
  • composer_line now accepts max_cols; tests updated.

^{Written for commit a738e47. Summary will update on new commits. Review in cubic}

[cubic-dev-ai]

1 issue found across 4 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="crates/cli/src/tui/app.rs">

<violation number="1" location="crates/cli/src/tui/app.rs:357">
P2: Inclusive iteration over a half-open visible window renders one extra cell beyond the width budget.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[cubic-dev-ai]

P2: Inclusive iteration over a half-open visible window renders one extra cell beyond the width budget.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At crates/cli/src/tui/app.rs, line 357:

<comment>Inclusive iteration over a half-open visible window renders one extra cell beyond the width budget.</comment>

<file context>
@@ -292,16 +292,69 @@ fn push_styled_run(
     let mut run_style: Option<Style> = None;
 
-    for idx in 0..=chars.len() {
+    for idx in win_start..=win_end {
         if idx == cursor_char_idx {
             let cursor_char = chars.get(idx).copied().unwrap_or(' ');
</file context>

[madebyaris]

Hi @titan That's look good, and thanks for your contribution.

Can you make it to merge DEV instead of main?

That would be great, thank you 👍