feat: Add arbitrary directory project storage with registry system

This major update replaces the fixed `generations/` directory with support
for storing projects in any directory on the filesystem. Projects are now
tracked via a cross-platform registry system.

## New Features

### Project Registry (`registry.py`)
- Cross-platform registry storing project name-to-path mappings
- Platform-specific config locations:
  - Windows: %APPDATA%\autonomous-coder\projects.json
  - macOS: ~/Library/Application Support/autonomous-coder/projects.json
  - Linux: ~/.config/autonomous-coder/projects.json
- POSIX path format for cross-platform compatibility
- File locking for concurrent access safety (fcntl/msvcrt)
- Atomic writes via temp file + rename to prevent corruption
- Fixed Windows file locking issue with tempfile.mkstemp()

### Filesystem Browser API (`server/routers/filesystem.py`)
- REST endpoints for browsing directories server-side
- Cross-platform support with blocked system paths:
  - Windows: C:\Windows, Program Files, ProgramData, etc.
  - macOS: /System, /Library, /private, etc.
  - Linux: /etc, /var, /usr, /bin, etc.
- Universal blocked paths: .ssh, .aws, .gnupg, .docker, etc.
- Hidden file detection (Unix dot-prefix + Windows attributes)
- UNC path blocking for security
- Windows drive enumeration via ctypes
- Directory creation with validation
- Added `has_children` field to DirectoryEntry schema

### UI Folder Browser (`ui/src/components/FolderBrowser.tsx`)
- React component for selecting project directories
- Breadcrumb navigation with clickable segments
- Windows drive selector
- New folder creation inline
- Fixed text visibility with explicit color values

## Updated Components

### Server Routers
- `projects.py`: Uses registry instead of fixed generations/ directory
- `agent.py`: Uses registry for project path lookups
- `features.py`: Uses registry for database path resolution
- `spec_creation.py`: Uses registry for WebSocket project resolution

### Process Manager (`server/services/process_manager.py`)
- Fixed sandbox issue: subprocess now uses project_dir as cwd
- This allows the Claude SDK sandbox to access external project directories

### Schemas (`server/schemas.py`)
- Added `has_children` to DirectoryEntry
- Added `in_progress` to ProjectStats
- Added path field to ProjectSummary and ProjectDetail

### UI Components
- `NewProjectModal.tsx`: Multi-step wizard with folder selection
- Added clarifying text about subfolder creation
- Fixed text color visibility issues

### API Client (`ui/src/lib/api.ts`)
- Added filesystem API functions (listDirectory, createDirectory)
- Fixed Windows path splitting for directory creation

### Documentation
- Updated CLAUDE.md with registry system details
- Updated command examples for absolute paths

## Security Improvements
- Blocked `.` and `..` in directory names to prevent traversal
- Added path blocking check in project creation
- UNC path blocking throughout filesystem API

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

ui/src/lib/api.ts

@@ -12,6 +12,8 @@ import type {
   AgentStatusResponse,
   AgentActionResponse,
   SetupStatus,
+  DirectoryListResponse,
+  PathValidationResponse,
 } from './types'
 
 const API_BASE = '/api'
@@ -41,10 +43,14 @@ export async function listProjects(): Promise<ProjectSummary[]> {
   return fetchJSON('/projects')
 }
 
-export async function createProject(name: string, specMethod: 'claude' | 'manual' = 'manual'): Promise<ProjectSummary> {
+export async function createProject(
+  name: string,
+  path: string,
+  specMethod: 'claude' | 'manual' = 'manual'
+): Promise<ProjectSummary> {
   return fetchJSON('/projects', {
     method: 'POST',
-    body: JSON.stringify({ name, spec_method: specMethod }),
+    body: JSON.stringify({ name, path, spec_method: specMethod }),
   })
 }
 
@@ -146,3 +152,59 @@ export async function getSetupStatus(): Promise<SetupStatus> {
 export async function healthCheck(): Promise<{ status: string }> {
   return fetchJSON('/health')
 }
+
+// ============================================================================
+// Filesystem API
+// ============================================================================
+
+export async function listDirectory(path?: string): Promise<DirectoryListResponse> {
+  const params = path ? `?path=${encodeURIComponent(path)}` : ''
+  return fetchJSON(`/filesystem/list${params}`)
+}
+
+export async function createDirectory(fullPath: string): Promise<{ success: boolean; path: string }> {
+  // Backend expects { parent_path, name }, not { path }
+  // Split the full path into parent directory and folder name
+
+  // Remove trailing slash if present
+  const normalizedPath = fullPath.endsWith('/') ? fullPath.slice(0, -1) : fullPath
+
+  // Find the last path separator
+  const lastSlash = normalizedPath.lastIndexOf('/')
+
+  let parentPath: string
+  let name: string
+
+  // Handle Windows drive root (e.g., "C:/newfolder")
+  if (lastSlash === 2 && /^[A-Za-z]:/.test(normalizedPath)) {
+    // Path like "C:/newfolder" - parent is "C:/"
+    parentPath = normalizedPath.substring(0, 3) // "C:/"
+    name = normalizedPath.substring(3)
+  } else if (lastSlash > 0) {
+    parentPath = normalizedPath.substring(0, lastSlash)
+    name = normalizedPath.substring(lastSlash + 1)
+  } else if (lastSlash === 0) {
+    // Unix root path like "/newfolder"
+    parentPath = '/'
+    name = normalizedPath.substring(1)
+  } else {
+    // No slash - invalid path
+    throw new Error('Invalid path: must be an absolute path')
+  }
+
+  if (!name) {
+    throw new Error('Invalid path: directory name is empty')
+  }
+
+  return fetchJSON('/filesystem/create-directory', {
+    method: 'POST',
+    body: JSON.stringify({ parent_path: parentPath, name }),
+  })
+}
+
+export async function validatePath(path: string): Promise<PathValidationResponse> {
+  return fetchJSON('/filesystem/validate', {
+    method: 'POST',
+    body: JSON.stringify({ path }),
+  })
+}

ui/src/lib/types.ts

@@ -12,6 +12,7 @@ export interface ProjectStats {
 
 export interface ProjectSummary {
   name: string
+  path: string
   has_spec: boolean
   stats: ProjectStats
 }
@@ -20,6 +21,35 @@ export interface ProjectDetail extends ProjectSummary {
   prompts_dir: string
 }
 
+// Filesystem types
+export interface DriveInfo {
+  letter: string
+  label: string
+  available?: boolean
+}
+
+export interface DirectoryEntry {
+  name: string
+  path: string
+  is_directory: boolean
+  has_children: boolean
+}
+
+export interface DirectoryListResponse {
+  current_path: string
+  parent_path: string | null
+  entries: DirectoryEntry[]
+  drives: DriveInfo[] | null
+}
+
+export interface PathValidationResponse {
+  valid: boolean
+  exists: boolean
+  is_directory: boolean
+  can_write: boolean
+  message: string
+}
+
 export interface ProjectPrompts {
   app_spec: string
   initializer_prompt: string