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>

server/services/spec_chat_session.py

@@ -95,7 +95,7 @@ class SpecChatSession:
         # Delete app_spec.txt so Claude can create it fresh
         # The SDK requires reading existing files before writing, but app_spec.txt is created new
         # Note: We keep initializer_prompt.md so Claude can read and update the template
-        from autocoder_paths import get_prompts_dir
+        from autoforge_paths import get_prompts_dir
         prompts_dir = get_prompts_dir(self.project_dir)
         app_spec_path = prompts_dir / "app_spec.txt"
         if app_spec_path.exists():
@@ -116,7 +116,7 @@ class SpecChatSession:
                 ],
             },
         }
-        from autocoder_paths import get_claude_settings_path
+        from autoforge_paths import get_claude_settings_path
         settings_file = get_claude_settings_path(self.project_dir)
         settings_file.parent.mkdir(parents=True, exist_ok=True)
         with open(settings_file, "w") as f: