[FEATURE] Include conversation title in statusline JSON

Problem Statement

Custom statuslines can show useful context like model, cost, cwd, and git branch - but there's no way to display which conversation/session the user is in. When working on multiple tasks or switching between terminals, users can't quickly identify their session without running claude --resume to see the list.

The conversation title is already computed and displayed in --resume output, so the data exists - it's just not exposed to the statusline.

Proposed Solution

Add a session.title field to the statusline JSON payload:

{
  "session_id": "abc123",
  "session": {
    "title": "Optimize Claude Code settings for faster team workflow"
  },
  ...existing fields...
}

This would allow statusline scripts to display the title at the end where it can naturally overflow:

Opus 4.5 | ~/project (main) | ctx: 45% | Optimize Claude Code settings for faster team workflow

Alternative Solutions

• Parse transcript_path: The transcript_path field points to the session file, which could be parsed for metadata. However, this adds latency to every statusline render and is fragile if the file format changes.
• Use session_id: Could display the raw ID, but it's not human-readable.

Priority

Medium - Would be very helpful

Feature Category

Configuration and settings

Use Case Example

1. Developer is working on multiple features across different terminals
2. Each terminal has a Claude Code session open
3. They switch to a terminal and see their custom statusline showing:

Opus 4.5 | ~/myapp (main) | ctx: 32% | Add authentication to API endpoints

1. They immediately know which task this session is for without running any commands
2. This prevents accidentally continuing work in the wrong session

Example statusline.sh

#!/bin/bash
input=$(cat)

MODEL=$(echo "$input" | jq -r '.model.display_name')
TITLE=$(echo "$input" | jq -r '.session.title // empty')
PCT=$(echo "$input" | jq -r '.context_window.used_percentage // 0' | cut -d. -f1)
CWD=$(echo "$input" | jq -r '.workspace.current_dir')

# Get git branch if in a repo
BRANCH=""
if git -C "$CWD" rev-parse --git-dir > /dev/null 2>&1; then
    BRANCH=$(git -C "$CWD" branch --show-current 2>/dev/null)
    [ -n "$BRANCH" ] && BRANCH=" ($BRANCH)"
fi

# Shorten path: replace home with ~, show last 2 dirs
SHORT_CWD=$(echo "$CWD" | sed "s|^$HOME|~|" | awk -F/ '{if(NF>2) print "…/"$(NF-1)"/"$NF; else print $0}')

# Title at end so it can overflow
if [ -n "$TITLE" ]; then
    echo "${MODEL} | ${SHORT_CWD}${BRANCH} | ctx: ${PCT}% | ${TITLE}"
else
    echo "${MODEL} | ${SHORT_CWD}${BRANCH} | ctx: ${PCT}%"
fi