feat: productivity suite — task loop, workflow, theming, docs & more (#197)

## Summary

A large productivity-focused feature branch delivering a suite of improvements across automation, project management, theming, performance, and documentation.

### Features

- **Guided Project Workflow** (#189) — Four-phase workflow panel (Discuss → Plan → Execute → Verify) to keep projects structured from idea to completion
- **Automated Task Loop** (#179) — Per-task conversation orchestration with wave-based parallel execution, blocked-task detection, and concurrency control
- **Wave-Based Parallel Execution** (#191) — Tasks run in dependency-aware waves with configurable concurrency; independent tasks execute in parallel
- **Auto-Commit After Task Completion** (#192) — Task Loop optionally commits after each completed task so progress is never lost
- **PRD Creator** (#180) — AI-assisted PRD and task list panel that outputs `hikari-tasks.json` for the Task Loop to consume
- **Project Context Panel** (#188) — Persistent `PROJECT.md`, `REQUIREMENTS.md`, `ROADMAP.md`, and `STATE.md` files injected into Claude's context automatically
- **Codebase Mapper** (#190) — Generates a `CODEBASE.md` architectural summary so Claude always understands the project structure
- **Community Preset Themes** (#181) — Six built-in community themes: Dracula, Catppuccin Mocha, Nord, Solarized Dark, Gruvbox Dark, and Rosé Pine
- **In-App Changelog Panel** (#193) — Fetches release notes from GitHub at runtime and displays them inside the app
- **Full Embedded Documentation** (#196) — Replaced the single-page help modal with a 12-page paginated docs browser featuring a sidebar TOC, prev/next navigation, keyboard navigation (arrow keys, `?` shortcut), and comprehensive coverage of every feature

### Performance & Fixes

- **Lazy Loading & Virtualisation** (#194) — Virtual windowing for conversation history, markdown memoisation, and debounced search for smooth rendering of large sessions
- **Ctrl+C Copy Fix** (#195) — `Ctrl+C` now copies selected text as expected; interrupt-Claude behaviour only fires when no text is selected

### UX

- Back-to-workflow button in PRD Creator and Task Loop panels for easy navigation
- Navigation icon cluster replaced with a single clean dropdown menu

## Closes

Closes #179
Closes #180
Closes #181
Closes #188
Closes #189
Closes #190
Closes #191
Closes #192
Closes #193
Closes #194
Closes #195
Closes #196

---

✨ This PR was created with help from Hikari~ 🌸

Reviewed-on: #197
Co-authored-by: Hikari <hikari@nhcarrigan.com>
Co-committed-by: Hikari <hikari@nhcarrigan.com>

PROJECT.md

@@ -0,0 +1,45 @@
+# Project Overview
+
+## What is this project?
+
+Hikari Desktop is a Tauri-based desktop application that wraps Claude Code with a visual anime character companion (Hikari) who appears on screen. It provides a rich UI for interacting with Claude Code, including conversation management, agent monitoring, cost tracking, and more.
+
+The app was inspired by a Hatsune Miku mod for the ship AI in _The Outer Worlds_ — the idea of an AI assistant with an anime girl avatar that you can actually _see_.
+
+## Goals
+
+- Provide a beautiful, personalised interface for Claude Code
+- Surface real-time status (thinking, typing, searching, etc.) through animated character sprites
+- Track costs, context usage, and agent activity across sessions
+- Support power-user workflows: multi-tab conversations, todo lists, git integration, MCP server management, session compaction, and more
+- Build a foundation for autonomous task execution (agent orchestration, PRD-driven workflows)
+
+## Tech Stack
+
+- **Frontend**: Svelte 5 + TypeScript + Tailwind CSS
+- **Backend**: Rust (Tauri v2)
+- **Build**: Vite + pnpm
+- **Testing**: Vitest (frontend) + cargo test (backend)
+- **Linting**: ESLint + Prettier (frontend) + Clippy (backend)
+- **IPC**: Tauri commands + events between Rust and Svelte
+
+## Architecture
+
+```
+hikari-desktop/
+├── src/                        # Svelte frontend
+│   └── lib/
+│       ├── components/         # UI components (panels, modals, status bar)
+│       ├── stores/             # Svelte stores (state management)
+│       ├── types/              # TypeScript type definitions
+│       └── utils/              # Utility functions
+├── src-tauri/                  # Rust backend
+│   └── src/
+│       ├── commands.rs         # Tauri command handlers
+│       ├── wsl_bridge.rs       # Claude Code process management
+│       ├── types.rs            # Shared types & CharacterState enum
+│       └── stats.rs            # Cost tracking
+└── public/                     # Static assets (sprites, sounds)
+```
+
+Claude Code is launched as a child process via `WslBridge`, communicating via `--output-format stream-json` (NDJSON). Messages flow from the Rust backend to the Svelte frontend via Tauri events.