feat(plugins): Sessions plugin for listing and deleting sessions

[clipod]

Summary

Adds a sessions plugin with /sessions:list and /sessions:delete commands — the most requested
session management feature in this repo.

• Project-scoped by default — only shows sessions for the current working directory, pass --all for
  all projects
• Cross-platform — macOS (~/.claude), Linux ($XDG_CONFIG_HOME/claude), Windows
  (%APPDATA%\claude), and $CLAUDE_CONFIG_DIR override
• Orphan detection — identifies conversation JSONL files that have no matching metadata
• Full cleanup — deletes session JSONL, metadata file, and subagent logs directory
• No unnecessary permission prompts — uses Read/Glob for discovery, only prompts for the actual
  deletion
• Safe — always asks for confirmation, refuses to delete the active session, no wildcards or
  recursive deletion

Closes #16901
Related: #18502, #19574, #23423, #23979, #25304, #13780, #19138, #21347

Note: This implements the slash command approach (/sessions:list, /sessions:delete) as a
plugin. The CLI flag approach (claude --list-sessions, claude --delete-session) mentioned in #16901
would require changes to the core codebase.

Files Changed

plugins/session-manager/
├── .claude-plugin/plugin.json # Plugin metadata
├── commands/
│ ├── list.md # /sessions:list [--all | search term]
│ └── delete.md # /sessions:delete [session-id | search | --all]
└── README.md

.claude-plugin/marketplace.json # Registered under "productivity" category

How It Works

/sessions:list

Uses Glob with a UUID pattern (????????-????-????-????-????????????.jsonl) to find session files while
excluding subagent logs in nested directories. Reads first lines to extract titles, matches against
metadata for start times. Sessions without metadata are marked [orphan].

/sessions:delete

Same discovery, then presents a numbered list. User selects by number, UUID, search term, or "all". After
confirmation, deletes:

1. {sessionId}/ subagent logs directory (rm -r)
2. {sessionId}.jsonl conversation data (rm)
3. {pid}.json metadata (rm)

Cross-Platform Config Resolution

Priority	Platform	Path
1	Any	$CLAUDE_CONFIG_DIR
2	Windows	%APPDATA%\claude → %LOCALAPPDATA%\claude → ~\.claude
3	Linux	$XDG_CONFIG_HOME/claude → ~/.claude
4	macOS	~/.claude

Test Plan

• /sessions:list shows only current project's sessions (no permission prompts)
• /sessions:list --all shows sessions across all projects
• /sessions:delete presents numbered list, asks for confirmation
• Deletion removes session JSONL, metadata JSON, and subagent directory
• Current active session is protected from deletion
• Orphaned sessions (JSONL without metadata) are detected and deletable
• UUID glob pattern excludes subagent files from listings
• Cross-platform path resolution tested on macOS

Context

This is one of the most requested features — #16901 has 44 upvotes with 8+ duplicate issues. While a
native CLI approach would require core changes, this plugin provides an immediate solution.