[FEATURE] Add ability to delete/manage past sessions

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

Currently there's no built-in way to delete or manage past Claude Code sessions. Users can only start new sessions or clear the current conversation context with /clear, but old sessions persist indefinitely in ~/.claude/projects/.

Proposed Solution

• A /sessions list command to view past sessions (date, summary, size)
• A /sessions delete <id> command to delete a specific session
• A /sessions prune --older-than 30d command to bulk-delete old sessions

Alternative Solutions

• Manually deleting files from ~/.claude/projects/ — works but is fragile, undocumented, and risks breaking state if the internal format changes

Priority

Medium - Would be very helpful

Feature Category

CLI commands and flags

Use Case Example

• Free up disk space by removing old, irrelevant sessions
• Remove sessions that contain sensitive information (credentials accidentally pasted, internal URLs, etc.)
• General housekeeping — after weeks of use, sessions accumulate with no way to prune them

Additional Context

_No response_