[FEATURE] Organize plans by 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

Can we please organize the plan files in ~/.claude/plans/ by projects the way logs are organized in ~/.claude/projects/

Proposed Solution

Can we please organize the plan files in ~/.claude/plans/ by projects the way logs are organized in ~/.claude/projects/

Alternative Solutions

_No response_

Priority

Critical - Blocking my work

Feature Category

CLI commands and flags

Use Case Example

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Additional Context

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