Conversation list always shows same +N -N diff stats even when git is clean and synced

Description

In the Claude Code conversation list, every conversation shows the same +183 -96 diff stat regardless of the actual git state. The number is identical across all conversations (Today, Yesterday, Older), even after the local branch is fully synced with remote.

Steps to Reproduce

1. Open a project with a git repository in Claude Code
2. Make some commits and push to remote
3. Verify git is clean: git status shows "nothing to commit, working tree clean" and "Your branch is up to date with 'origin/main'"
4. Open the conversation list sidebar

Expected Behavior

Either:

• Show +0 -0 (or nothing) when the working tree is clean and in sync with remote
• Or show per-conversation accurate diff stats reflecting what changed during each conversation

Actual Behavior

Every single conversation in the list shows the same +183 -96, even for older conversations and even when git status confirms the repo is fully clean and synced with remote.

Environment

• macOS 25.3.0 (Darwin)
• Claude Code (Sonnet 4.6)