[FEATURE] Global session listing across all projects

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

Sessions are scoped to the project directory where they started. When working across multiple projects, I often forget which folder a specific conversation was in. The only way to find it is manually browsing ~/.claude/projects/ subdirectories, which is tedious and break my workflow.

Proposed Solution

Add a --global or --all flag to the resume command

The session picker would display sessions from all projects, showing the project path alongside:
[~/projects/ML_learning] Implemented random forest - 2h ago
[~/projects/api_backend] Fixed auth middleware - 1d ago
[~/projects/frontend] Added dark mode toggle - 3d ago

Alternative Solutions

Currently I work around this by:

• Running find ~/.claude -name "*.json" -path "*/sessions/*" to locate session files
• Manually remembering which project each conversation belonged to

Priority

Medium - Would be very helpful

Feature Category

CLI commands and flags

Use Case Example

Use Case Example:

1. I start a conversation in ~/projects/ML_learning about training a model
2. Switch to ~/projects/api_backend for unrelated work
3. Days later, want to continue the ML conversation but forgot which folder
4. Run claude --resume - nothing shows up (wrong directory)
5. With --global flag, I'd see all recent sessions across projects and pick the right one

Additional Context

Additional Context:
Related issues: #1340, #371, #12052
Multiple bug reports about resume not finding sessions suggest users expect more flexible session access.