Remove obsolete GitHub Actions workflows per subtraction-creates-value

## Summary
Remove outdated and unused GitHub Actions workflows that are creating noise without value.

## Analysis

### 1. claude-code-pr-generator.yml - OBSOLETE
- **950 workflow runs, ALL skipped** (massive waste)
- Replaced by `claude-implementation.yml`
- Uses old `@anthropic-ai/claude-code` npm package
- Triggers on `ai-generate` label that's never actually used
- Has stale docs in `.github/workflows/docs/claude-code-pr-generator.md`

### 2. test-mcp-server.yml - LIKELY OBSOLETE
- Shows in API but may not exist in current directory
- If exists, likely outdated MCP testing replaced by better methods

## Workflows to Keep (But Worth Noting)

These workflows are rarely triggered but serve valid purposes:

- **validate-secrets.yml** - Only runs when `.bash_secrets.example` changes
- **test-arch-install.yml** - Only runs on arch-specific path changes
- **test-general-dotfiles-setup.yml** - Only runs on setup script changes
- **validate-dotfiles.yml** - Validates bash scripts on main push

## Implementation Plan

1. Delete `.github/workflows/claude-code-pr-generator.yml`
2. Delete `.github/workflows/docs/claude-code-pr-generator.md`
3. Check for and delete `test-mcp-server.yml` if it exists
4. Clean up any references to removed workflows

## Impact
- **Removes 950 useless workflow runs** from history
- Reduces confusion about which workflows are active
- Cleaner, more maintainable codebase
- Follows subtraction-creates-value principle

## Success Criteria
- [ ] Obsolete workflows deleted
- [ ] Associated documentation removed
- [ ] No broken references remain
- [ ] GitHub Actions page shows only active, useful workflows

## Principles
- **subtraction-creates-value**: Strategic removal creates more value than addition
- **systems-stewardship**: Keep systems clean and maintainable

Start by checking .github/workflows/claude-code-pr-generator.yml, .github/workflows/docs/claude-code-pr-generator.md, and whether test-mcp-server.yml exists. Search the repository for references to these workflows before removing them. Done means the obsolete files and references are gone, with only the intended active workflows remaining.

Written by the indexing model from the issue text.