Task list: allow expanding truncated task titles

Problem

When Claude creates tasks via TaskCreate, the task list sidebar truncates long subject lines with an ellipsis (…) and there's no way to see the full text. There is no hover tooltip, click-to-expand, keyboard shortcut, or any other mechanism to reveal the full title.

There's no length limit on the subject or description fields in the tool schema, so Claude can generate arbitrarily long titles — but the UI hard-truncates them to fit the terminal width.

How truncation works (from source)

The subject display width is calculated as:

maxWidth = Math.max(15, terminalColumns - 15 - ownerLabelWidth)

The C7 truncation function then clips the subject to this width using Intl.Segmenter, appending … if truncated. The full string is stored in the task data but never accessible through the UI.

This makes it hard to distinguish between tasks with similar prefixes or understand what a task is about when the meaningful part gets cut off.

Current behavior

• Task titles are truncated to columns - 15 - ownerWidth characters with …
• No interaction reveals the full text
• Ctrl+T toggles visibility but doesn't help with truncation
• The only workaround is asking Claude to call TaskGet in the conversation, which breaks flow

Proposed solution

Any of the following would work:

1. Hover tooltip — show full title on mouse hover (terminals with mouse support)
2. Arrow key navigation + expand — let users navigate the task list and press Enter/Space to expand
3. Wrap instead of truncate — allow long titles to wrap to multiple lines
4. Ctrl+T cycling — cycle between hidden → compact → expanded views instead of just toggle

Option 2 or 4 would be most terminal-friendly.