rebrand: rename AutoCoder to AutoForge across entire codebase

Complete project rebrand from AutoCoder to AutoForge, touching 62 files
across Python backend, FastAPI server, React UI, documentation, config,
and CI/CD.

Key changes:
- Rename autocoder_paths.py -> autoforge_paths.py with backward-compat
  migration from .autocoder/ -> .autoforge/ directories
- Update registry.py to migrate ~/.autocoder/ -> ~/.autoforge/ global
  config directory with fallback support
- Update security.py with fallback reads from legacy .autocoder/ paths
- Rename .claude/commands and skills from gsd-to-autocoder-spec to
  gsd-to-autoforge-spec
- Update all Python modules: client, prompts, progress, agent,
  orchestrator, server routers and services
- Update React UI: package.json name, index.html title, localStorage
  keys, all documentation sections, component references
- Update start scripts (bat/sh/py), examples, and .env.example
- Update CLAUDE.md and README.md with new branding and paths
- Update test files for new .autoforge/ directory structure
- Transfer git remote from leonvanzyl/autocoder to
  AutoForgeAI/autoforge

Backward compatibility preserved: legacy .autocoder/ directories are
auto-detected and migrated on next agent start. Config fallback chain
checks both new and old paths.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

ui/src/components/docs/sections/AdvancedConfig.tsx

@@ -129,7 +129,7 @@ ANTHROPIC_DEFAULT_SONNET_MODEL=qwen3-coder`}</code></pre>
         Environment Variables
       </h3>
       <p className="text-muted-foreground mb-3">
-        Key environment variables for configuring AutoCoder:
+        Key environment variables for configuring AutoForge:
       </p>
       <table className="w-full text-sm mt-3">
         <thead>
@@ -193,7 +193,7 @@ ANTHROPIC_DEFAULT_SONNET_MODEL=qwen3-coder`}</code></pre>
         Webhook Support
       </h3>
       <ul className="list-disc space-y-2 ml-4 text-muted-foreground">
-        <li>AutoCoder can send webhook notifications on feature completion</li>
+        <li>AutoForge can send webhook notifications on feature completion</li>
         <li>Compatible with N8N and similar automation tools</li>
         <li>Configure the webhook URL in project settings</li>
         <li>
@@ -208,7 +208,7 @@ ANTHROPIC_DEFAULT_SONNET_MODEL=qwen3-coder`}</code></pre>
       <ul className="list-disc space-y-2 ml-4 text-muted-foreground">
         <li>
           All projects are registered in{' '}
-          <span className="bg-muted px-1.5 py-0.5 rounded text-sm font-mono">~/.autocoder/registry.db</span>{' '}
+          <span className="bg-muted px-1.5 py-0.5 rounded text-sm font-mono">~/.autoforge/registry.db</span>{' '}
           (SQLite)
         </li>
         <li>Maps project names to filesystem paths</li>