chore: add CLAUDE.md for Claude Code development guidance

CLAUDE.md

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+# CLAUDE.md
+
+This document helps Claude understand the Sleuth repo structure and common development patterns.
+
+## Project Overview
+
+Sleuth is an Electron-based Slack Log Viewer application built with React, TypeScript, and MobX for state management. It processes various types of log files (browser, webapp, mobile, installer, etc.) and provides a comprehensive UI for viewing, filtering, and analyzing log data.
+
+## Development Commands
+
+IMPORTANT: Never attempt to run `npm`, instead always run the equivalent `yarn` command
+
+### Core Commands
+
+- `yarn install` - Install dependencies
+- `yarn start` - Start development build with Electron
+- `yarn test` - Run tests with Vitest
+- `yarn run tsc` - TypeScript type checking
+- `yarn run lint` - Run linting (includes TypeScript check, ESLint, and Prettier)
+- `yarn run lint:fix` - Fix linting issues automatically
+
+### Build Commands
+
+note that you (Claude) should avoid running these commands  as they are slow, instead prefer running test, tsc or lint to validate changes rapidly.
+
+- `yarn run package` - Package the app for current platform
+- `yarn run make` - Create distributable for current platform
+- `yarn run publish` - Publish to configured distributors
+
+### Utility Commands
+
+- `yarn run catapult:update` - Update catapult submodule
+
+## Architecture
+
+### Electron Architecture
+
+The app follows standard Electron patterns with three main processes:
+
+- **Main Process** (`src/main/index.ts`): Application lifecycle, window management, IPC handling, file system operations
+- **Renderer Process** (`src/renderer/renderer.ts`): React UI rendering
+- **Preload Script** (`src/preload/preload.ts`): Secure bridge exposing `window.Sleuth` API to renderer
+
+### Key Components
+
+#### State Management
+
+- **SleuthState** (`src/renderer/state/sleuth.ts`): Main MobX store managing log files, selected entries, filters, bookmarks, and UI state
+- Uses MobX observables with React integration via `mobx-react`
+
+#### Log Processing
+
+- **Processor** (`src/renderer/processor.ts`): Core log file parsing and processing logic
+- Handles multiple log types: browser, webapp, mobile, installer, chromium, netlog, trace, state
+- Converts raw log files into structured `LogEntry` objects with timestamps, levels, and metadata
+
+#### UI Structure
+
+- **App** (`src/renderer/components/app.tsx`): Root component
+- **AppCore** (`src/renderer/components/app-core.tsx`): Main application layout
+- **LogTable** (`src/renderer/components/log-table.tsx`): Virtualized log entry display
+- **Sidebar** (`src/renderer/components/sidebar/`): File tree, bookmarks, and navigation
+- **Preferences** (`src/renderer/components/preferences/`): Settings and configuration
+
+#### Key Interfaces
+
+- **LogEntry** (`src/interfaces.ts`): Core data structure for log entries
+- **UnzippedFile/ProcessedLogFile/MergedLogFile**: File handling abstractions
+- **LogType** enum: Defines supported log file types
+
+### IPC Communication
+
+- **IpcEvents** (`src/ipc-events.ts`): Defines all IPC channel constants
+- **IPC Manager** (`src/main/ipc.ts`): Handles main process IPC routing
+- **SleuthAPI** (preload): Exposed renderer API with type safety
+
+### Specialized Features
+
+- **Trace Analysis**: Chrome DevTools and Perfetto trace file support
+- **State Inspection**: Redux state visualization
+- **NetLog Viewing**: Network log analysis
+- **Bookmarking**: Save and restore specific log entries
+- **Log Merging**: Combine multiple log files chronologically
+
+## Testing
+
+- Uses Vitest with jsdom environment
+- Test files: `test/**/*.test.[jt]s?(x)`
+- Setup: `test/vitest-setup.js`
+- Global test utilities available
+
+## Code Conventions
+
+### ESLint Rules
+
+- Strict separation: renderer code cannot import Node.js modules (fs, path, etc.)
+- Use `@typescript-eslint` for TypeScript-specific rules
+- Unused vars prefixed with `_` are ignored
+
+### File Organization
+
+- `src/main/`: Main process Electron code
+- `src/renderer/`: React renderer code
+- `src/preload/`: Preload script for secure IPC
+- `src/utils/`: Shared utilities (renderer-safe only)
+- `src/interfaces.ts`: Shared TypeScript interfaces
+
+### State Patterns
+
+- Use MobX `@observable` and `@action` decorators
+- State mutations only through actions
+- Computed values for derived data
+- Autorun for side effects
+
+## Development Notes
+
+IMPORTANT: never disable a lint rule or add @ts-ignore unless explicitly asked to do so by the user.
+If you are unable to solve a problem without disabling a lint rule, stop and ask the user for
+guidance first.
+
+**CRITICAL: NEVER use --no-verify flag with git commands.** This bypasses pre-commit hooks that enforce code quality and can introduce broken code into the repository. Always fix the underlying issues that cause hooks to fail instead of bypassing them. If a hook is failing, address the specific linting, formatting, or test failures it identifies.
+
+### Security
+
+- Context isolation enabled - use `contextBridge` in preload
+- Renderer process has restricted Node.js access
+- File operations must go through IPC to main process
+
+### Performance
+
+- Log table uses `react-virtualized` for large datasets
+- Log processing happens in chunks to avoid blocking UI
+- Background processing for heavy operations
+
+### Platform Support
+
+- Cross-platform Electron app (macOS, Windows, Linux)
+- Platform-specific code paths handled via `process.platform`