Auto-issue bodies should indicate whether findings are auto-fixable

[chubes4]

Context

When homeboy-action creates categorized audit/lint/test issues, the issue body lists findings but doesn't say whether they're auto-fixable. You have to run homeboy audit --fix locally to find out which categories have working fixers.

Proposal

Add an auto-fix status section to the generated issue body. The data is already available at audit time — homeboy knows which findings it can generate fixes for and which it can't.

For audit issues

## Auto-fix status
✅ 270/270 findings auto-fixable
Run: `homeboy audit data-machine --fix --write --only duplicate_function`

or

## Auto-fix status
❌ No fixer available for `unused_parameter`

or partial:

## Auto-fix status
⚠️ 6/17 findings auto-fixable (11 skipped — parser limitations)
Run: `homeboy audit data-machine --fix --write --only broken_doc_reference`

For lint issues

## Auto-fix status
✅ Auto-fixable via `homeboy lint data-machine --fix`

or

## Auto-fix status
❌ Manual fix required (database queries need review)

Implementation

homeboy-action already runs the audit/lint commands and gets structured output. It just needs to:

1. Check if the finding category has a fixer (audit: from --fix dry run or a capability map; lint: from PHPCS phpcbf fixability)
2. Include the status line in the issue body template

This could be a static capability map in homeboy core (simplest) or derived from the actual --fix output (most accurate but slower).