Add development-friendly class reloading support to avoid "already defined" errors

[delano]

Problem

When reloading Familia model classes during development (e.g., via load in IRB), the system throws ArgumentError for already defined methods:

irb> load 'examples/autoloader/mega_customer.rb'
# => true (first time)

irb> load 'examples/autoloader/mega_customer.rb'  
# ArgumentError: Method >>> custid <<< already defined for MegaCustomer

This makes iterative development and debugging difficult, requiring IRB restarts to test class changes.

Root Cause

1. Familia field definitions create getter/setter methods via define_method
2. On reload, the class constant still exists with previously defined methods
3. FieldType#handle_method_conflict defaults to :raise strategy
4. Ruby 3.2+ changes around class redefinition make this behavior more prominent

Proposed Solution

Add opt-in reloading support using Ruby's remove_const for clean class unloading:

1. Reloadable Feature Module (lib/familia/features/reloadable.rb)

• Provides reload! and unload! class methods
• Handles constant removal and file reloading
• Tracks source file locations

2. Development Helper Utilities (lib/familia/reload_helper.rb)

• IRB-friendly methods: Familia.reload_class(klass_or_path)
• Class tracking and management
• Safe constant removal patterns

3. Enhanced Examples

• Demonstrate proper reloading workflow
• Show feature usage in development

Usage Example

class MegaCustomer < Familia::Horreum
  include Familia::Features::Reloadable
  field :custid
  field :username
  # ...
end

# In IRB development:
MegaCustomer.reload!  # Cleanly reloads from source file
# Or using helper:
Familia.reload_class('examples/autoloader/mega_customer.rb')

Design Principles

• Preserve intentional behavior: Keep default error-raising for production safety
• Opt-in only: No changes to existing field definition behavior
• Ruby 3.2+ idiomatic: Use remove_const following modern Ruby patterns
• Development-focused: Designed for IRB/console workflows, not automatic reloading

Technical Details

See technical analysis in Serena memory class-reloading-technical-analysis for comprehensive implementation details, Ruby 3.2+ considerations, ORM pattern research, and detailed architecture specifications.

Benefits

• Faster development iteration cycles
• No more IRB restarts for class changes
• Maintains production safety guarantees
• Follows Ruby community best practices
• Zero performance impact on production code