Allow `--resume` to access conversations from any directory

Description

Currently, claude --resume <session-id> only works when run from the same directory where the conversation was originally created. If that directory is deleted or renamed, the conversation becomes inaccessible even though the session data still exists in ~/.claude/projects/.

Use case

• I had a conversation in /path/to/project-a with session ID 0e3faa5f-...
• The directory was deleted/renamed
• Running claude --resume 0e3faa5f-... from any other directory fails with "No conversation found"
• The session file still exists at ~/.claude/projects/-path-to-project-a/0e3faa5f-....jsonl

Proposed solution

Add a flag like --global or change --resume <id> to search all project directories when an explicit session ID is provided:

claude --resume 0e3faa5f-... --global
# or just make --resume <explicit-id> search globally

Workaround

Currently requires manually copying the .jsonl file between ~/.claude/projects/ subdirectories or recreating the original directory.