[Feature Request] Add 'Solo Dev Mode' for handling pre-existing issues

Problem

Claude Code currently skips pre-existing bugs during task execution, labeling them as "pre-existing issues, not introduced by this change."

This creates two problems:

1. Misattribution — Claude sometimes introduces bugs itself, then incorrectly labels them as pre-existing
2. Solo developer gap — For solo developers, there's no team to fix these issues. When Claude skips them, they never get fixed

Proposed Solution

Add a mode toggle (via flag, config, or /mode command):

• Team Dev Mode (current default): Scope work to current task, flag pre-existing issues but don't fix them
• Solo Dev Mode: Treat entire project as Claude's responsibility, fix pre-existing issues encountered during tasks

Why This Matters

Solo developers and small teams don't have dedicated resources to handle pre-existing issues. For them, "pre-existing" effectively means "won't be fixed."

A simple mode toggle would make Claude Code significantly more useful for this audience without changing the team development experience.

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Environment: Claude Code (latest), macOS
Type: Feature Request