chore: scaffold Tauri 2 + Svelte 5 workspace

Standard Tauri layout with a Svelte 5 + TypeScript + Vite frontend and a
Rust backend in src-tauri. Adds build tooling, app/window config,
capabilities, generated icons and the project README.

.gitignore

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+# Rust / Tauri
+/src-tauri/target
+/src-tauri/gen/schemas
+/target
+
+# Node
+node_modules
+dist
+dist-ssr
+.DS_Store
+
+# Vite
+*.local
+
+# Logs
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+pnpm-debug.log*
+
+# Editor
+.vscode/*
+!.vscode/extensions.json
+.idea

README.md

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+# Mermix
+
+A cross-platform **Mermaid diagram editor & viewer** with **Git-backed projects**.
+Organize many diagrams into projects, edit them with a live preview, export to
+SVG/PNG, and version everything with real Git branches and commits — all in a
+native desktop app.
+
+Built with **Rust + Tauri 2**, **SQLite (sqlx)**, **git2**, and a **Svelte 5 +
+TypeScript** frontend using **CodeMirror 6** and **Mermaid 11**.
+
+---
+
+## Features
+
+- **Projects** — each project is a folder on disk that is a real Git repository
+  with a `mermix.toml` config and a `diagrams/` directory of `.mmd` files.
+- **Many diagrams per project** with a sidebar explorer; create, rename, delete.
+- **Live editor + preview** — CodeMirror source on the left, debounced Mermaid
+  render on the right, with zoom/pan and inline syntax-error reporting.
+- **Git version control built in** — view the working-tree status, write commit
+  messages, browse history, create branches and switch between them. Each branch
+  keeps its own set of diagrams, just like normal Git.
+- **Export** the current diagram to **SVG** or **PNG** (2× scale).
+- **Project registry** — recently opened projects are remembered in a local
+  SQLite database so you can jump back in from the start screen.
+- **Themes** — switch the Mermaid theme (default / neutral / dark / forest /
+  base) per project.
+
+## Architecture
+
+```
+Mermix/
+├─ src/                     # Svelte 5 + TS frontend
+│  ├─ App.svelte            # layout, resizable editor/preview split
+│  ├─ lib/
+│  │  ├─ api.ts             # typed wrappers over Tauri commands
+│  │  ├─ store.svelte.ts    # central rune-based app state
+│  │  ├─ mermaid.ts         # render + error capture
+│  │  ├─ export.ts          # SVG / PNG export via save dialog
+│  │  └─ components/        # Sidebar, Editor, Preview, GitPanel, Toolbar, …
+│  └─ main.ts
+└─ src-tauri/               # Rust backend
+   ├─ src/
+   │  ├─ lib.rs             # Tauri builder, state, command registry
+   │  ├─ commands.rs        # the IPC surface
+   │  ├─ db.rs              # sqlx/SQLite project registry + settings
+   │  ├─ project.rs         # mermix.toml, create/open, slugify
+   │  ├─ diagram.rs         # .mmd CRUD, frontmatter titles
+   │  ├─ git_ops.rs         # git2: commit, history, branches, status
+   │  ├─ error.rs / state.rs
+   │  └─ tests.rs           # headless core-logic tests
+   └─ tauri.conf.json
+```
+
+**Data model.** Mermix keeps one small app-level SQLite database (in the OS app
+data directory) that only tracks the *registry* of known projects and user
+settings. All real content lives on disk inside each project's Git repository —
+so projects are portable, inspectable, and work with any other Git tooling.
+
+A project on disk looks like:
+
+```
+my-diagrams/
+├─ mermix.toml          # project id, name, description, default theme
+├─ README.md
+├─ .gitignore
+├─ .git/                # full Git history
+└─ diagrams/
+   ├─ welcome.mmd
+   └─ login-flow.mmd    # Mermaid source, optional YAML frontmatter title
+```
+
+## Prerequisites
+
+- **Rust** (stable) and **Cargo**
+- **Node.js** 18+ and npm
+- Platform webview deps:
+  - **macOS** — nothing extra (system WebKit)
+  - **Windows** — WebView2 (preinstalled on Windows 11)
+  - **Linux** — `webkit2gtk` and related packages (see Tauri docs)
+
+## Getting started
+
+```bash
+npm install          # install frontend deps + Tauri CLI
+
+npm run app:dev      # run the desktop app in dev mode (hot reload)
+npm run app:build    # build a production bundle for your platform
+```
+
+Other useful scripts:
+
+```bash
+npm run dev          # frontend only (Vite) on http://localhost:1420
+npm run build        # type-check + build the frontend bundle
+npm run check        # svelte-check type checking
+```
+
+Backend logic is covered by headless tests:
+
+```bash
+cd src-tauri && cargo test
+```
+
+## Keyboard shortcuts
+
+| Shortcut            | Action                |
+| ------------------- | --------------------- |
+| `⌘/Ctrl + S`        | Save current diagram  |
+| `⌘/Ctrl + Enter`    | Commit (in commit box)|
+| `⌘/Ctrl + scroll`   | Zoom the preview      |
+
+## How Git is used
+
+- Creating a project runs `git init` (default branch `main`) and makes an
+  initial commit.
+- **Commit** stages every change (adds, edits, deletes) and records it with the
+  message you type; the author defaults to your global Git identity, falling back
+  to `Mermix <mermix@localhost>` if none is configured.
+- **Branches** are listed in the Git panel; create one and Mermix checks it out
+  for you. Switching branches reloads the diagram list from that branch.
+- **History** shows the most recent commits with short SHA, message, author and
+  relative time.
+
+## License
+
+MIT

index.html

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+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <link rel="icon" type="image/svg+xml" href="/mermix.svg" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>Mermix</title>
+  </head>
+  <body>
+    <div id="app"></div>
+    <script type="module" src="/src/main.ts"></script>
+  </body>
+</html>

package.json

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+{
+  "name": "mermix",
+  "version": "0.1.0",
+  "description": "Cross-platform Mermaid diagram editor & viewer with Git-backed projects",
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "svelte-check --tsconfig ./tsconfig.json && vite build",
+    "preview": "vite preview",
+    "check": "svelte-check --tsconfig ./tsconfig.json",
+    "tauri": "tauri",
+    "app:dev": "tauri dev",
+    "app:build": "tauri build"
+  },
+  "dependencies": {
+    "@codemirror/commands": "^6.6.0",
+    "@codemirror/language": "^6.10.2",
+    "@codemirror/state": "^6.4.1",
+    "@codemirror/view": "^6.28.0",
+    "@tauri-apps/api": "^2.0.0",
+    "@tauri-apps/plugin-dialog": "^2.0.0",
+    "codemirror": "^6.0.1",
+    "mermaid": "^11.2.0"
+  },
+  "devDependencies": {
+    "@sveltejs/vite-plugin-svelte": "^4.0.0",
+    "@tauri-apps/cli": "^2.0.0",
+    "@tsconfig/svelte": "^5.0.4",
+    "svelte": "^5.1.0",
+    "svelte-check": "^4.0.0",
+    "tslib": "^2.7.0",
+    "typescript": "^5.6.0",
+    "vite": "^5.4.0"
+  }
+}

public/mermix.svg

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+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 256" width="256" height="256">
+  <defs>
+    <linearGradient id="g" x1="0" y1="0" x2="1" y2="1">
+      <stop offset="0" stop-color="#a78bfa"/>
+      <stop offset="1" stop-color="#7c5cff"/>
+    </linearGradient>
+  </defs>
+  <rect width="256" height="256" rx="56" fill="#171a21"/>
+  <g fill="none" stroke="url(#g)" stroke-width="14" stroke-linecap="round" stroke-linejoin="round">
+    <rect x="48" y="40" width="72" height="44" rx="10"/>
+    <rect x="136" y="40" width="72" height="44" rx="10"/>
+    <rect x="92" y="160" width="72" height="44" rx="10"/>
+    <path d="M84 84 L128 160"/>
+    <path d="M172 84 L128 160"/>
+  </g>
+  <g fill="url(#g)">
+    <circle cx="84" cy="84" r="9"/>
+    <circle cx="172" cy="84" r="9"/>
+    <circle cx="128" cy="160" r="9"/>
+  </g>
+</svg>

src-tauri/Cargo.toml

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+[package]
+name = "mermix"
+version = "0.1.0"
+description = "Cross-platform Mermaid editor & viewer with Git-backed projects"
+authors = ["Mermix"]
+edition = "2021"
+rust-version = "1.77"
+
+[lib]
+# The `_lib` suffix keeps the library name distinct from the binary so the
+# Tauri mobile bindings can link against it.
+name = "mermix_lib"
+crate-type = ["staticlib", "cdylib", "rlib"]
+
+[build-dependencies]
+tauri-build = { version = "2", features = [] }
+
+[dependencies]
+tauri = { version = "2", features = [] }
+tauri-plugin-dialog = "2"
+
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"
+
+# App-level metadata store (project registry + settings).
+sqlx = { version = "0.8", default-features = false, features = [
+    "runtime-tokio",
+    "sqlite",
+    "chrono",
+    "macros",
+] }
+
+# Per-project version control.
+git2 = "0.19"
+
+tokio = { version = "1", features = ["rt-multi-thread", "macros", "fs", "sync"] }
+thiserror = "1"
+chrono = { version = "0.4", features = ["serde"] }
+uuid = { version = "1", features = ["v4", "serde"] }
+directories = "5"
+toml = "0.8"
+
+[features]
+# This feature is used for production builds or when a dev server is not
+# specified, DO NOT REMOVE!!
+custom-protocol = ["tauri/custom-protocol"]
+
+[profile.release]
+panic = "abort"
+codegen-units = 1
+lto = true
+opt-level = "s"
+strip = true

src-tauri/build.rs

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+fn main() {
+    tauri_build::build()
+}

src-tauri/capabilities/default.json

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+{
+  "$schema": "../gen/schemas/desktop-schema.json",
+  "identifier": "default",
+  "description": "Default permissions for the Mermix main window",
+  "windows": ["main"],
+  "permissions": [
+    "core:default",
+    "core:window:allow-start-dragging",
+    "core:window:allow-set-title",
+    "dialog:default",
+    "dialog:allow-open",
+    "dialog:allow-save",
+    "dialog:allow-message",
+    "dialog:allow-ask"
+  ]
+}

src-tauri/icons/android/mipmap-anydpi-v26/ic_launcher.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+  <foreground android:drawable="@mipmap/ic_launcher_foreground"/>
+  <background android:drawable="@color/ic_launcher_background"/>
+</adaptive-icon>

src-tauri/icons/android/values/ic_launcher_background.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+  <color name="ic_launcher_background">#fff</color>
+</resources>

src-tauri/tauri.conf.json

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+{
+  "$schema": "https://schema.tauri.app/config/2",
+  "productName": "Mermix",
+  "version": "0.1.0",
+  "identifier": "dev.mermix.app",
+  "build": {
+    "beforeDevCommand": "npm run dev",
+    "devUrl": "http://localhost:1420",
+    "beforeBuildCommand": "npm run build",
+    "frontendDist": "../dist"
+  },
+  "app": {
+    "windows": [
+      {
+        "title": "Mermix",
+        "width": 1280,
+        "height": 820,
+        "minWidth": 880,
+        "minHeight": 560,
+        "resizable": true,
+        "fullscreen": false,
+        "center": true
+      }
+    ],
+    "security": {
+      "csp": null
+    }
+  },
+  "bundle": {
+    "active": true,
+    "targets": "all",
+    "icon": [
+      "icons/32x32.png",
+      "icons/128x128.png",
+      "icons/128x128@2x.png",
+      "icons/icon.icns",
+      "icons/icon.ico"
+    ],
+    "category": "DeveloperTool",
+    "shortDescription": "Mermaid editor & viewer with Git-backed projects",
+    "longDescription": "Mermix is a cross-platform Mermaid diagram editor and viewer. Organize many diagrams into projects backed by Git for branches, versions and commit history."
+  },
+  "plugins": {}
+}

svelte.config.js

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+import { vitePreprocess } from '@sveltejs/vite-plugin-svelte';
+
+export default {
+  preprocess: vitePreprocess(),
+};

tsconfig.json

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+{
+  "extends": "@tsconfig/svelte/tsconfig.json",
+  "compilerOptions": {
+    "target": "ESNext",
+    "useDefineForClassFields": true,
+    "module": "ESNext",
+    "resolveJsonModule": true,
+    "allowJs": true,
+    "checkJs": true,
+    "isolatedModules": true,
+    "moduleDetection": "force",
+    "moduleResolution": "bundler",
+    "strict": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "skipLibCheck": true
+  },
+  "include": ["src/**/*.ts", "src/**/*.d.ts", "src/**/*.svelte", "vite.config.ts"],
+  "references": [{ "path": "./tsconfig.node.json" }]
+}

tsconfig.node.json

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+{
+  "compilerOptions": {
+    "composite": true,
+    "skipLibCheck": true,
+    "module": "ESNext",
+    "moduleResolution": "bundler",
+    "allowSyntheticDefaultImports": true,
+    "strict": true
+  },
+  "include": ["vite.config.ts"]
+}

vite.config.ts

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+import { defineConfig } from 'vite';
+import { svelte } from '@sveltejs/vite-plugin-svelte';
+
+const host = process.env.TAURI_DEV_HOST;
+
+// https://vitejs.dev/config/
+export default defineConfig(async () => ({
+  plugins: [svelte()],
+
+  // Tauri expects a fixed port and fails if it is not available.
+  clearScreen: false,
+  server: {
+    port: 1420,
+    strictPort: true,
+    host: host || false,
+    hmr: host
+      ? {
+          protocol: 'ws',
+          host,
+          port: 1421,
+        }
+      : undefined,
+    watch: {
+      // Don't watch the Rust backend; tauri handles that.
+      ignored: ['**/src-tauri/**'],
+    },
+  },
+
+  // Produce smaller, debuggable bundles depending on the Tauri build profile.
+  envPrefix: ['VITE_', 'TAURI_'],
+  build: {
+    target: process.env.TAURI_ENV_PLATFORM === 'windows' ? 'chrome105' : 'safari13',
+    minify: !process.env.TAURI_ENV_DEBUG ? 'esbuild' : false,
+    sourcemap: !!process.env.TAURI_ENV_DEBUG,
+  },
+}));