Add hybrid versioning scripts, version shown in app footer

docs/README.dev-notes.md

@@ -8,6 +8,55 @@
 - **Recharts 3.3.0** for data visualization
 - **Vite 5** as build tool
 
+## Version Management
+
+The project uses a **hybrid versioning approach**:
+- **Semver** (e.g., `0.2.1`) in `package.json` for npm ecosystem compatibility
+- **Git hash** (e.g., `+a3f2b9c`) automatically appended at build time
+- **Displayed version** in UI footer: `0.2.1+a3f2b9c` (or `0.2.1+a3f2b9c-dirty` if uncommitted changes)
+
+### Version Scripts
+
+```sh
+# Bump version manually (updates package.json)
+npm run version:patch  # 0.2.1 → 0.2.2 (bug fixes)
+npm run version:minor  # 0.2.1 → 0.3.0 (new features)
+npm run version:major  # 0.2.1 → 1.0.0 (breaking changes)
+
+# Generate version.json with git info (runs automatically on build)
+npm run prebuild
+
+# Build for production (automatically generates version)
+npm run build
+```
+
+### How It Works
+
+1. **Manual semver bump**: Run `npm run version:patch|minor|major` when you want to increment the version
+2. **Automatic git info**: On build, `scripts/generate-version.js` creates `src/version.json` with:
+   - `version`: Semver + git hash (e.g., `0.2.1+a3f2b9c`)
+   - `semver`: Just the semver (e.g., `0.2.1`)
+   - `commit`: Git commit hash (e.g., `a3f2b9c`)
+   - `branch`: Current git branch
+   - `buildDate`: ISO timestamp
+   - `gitDate`: Commit date
+3. **Fallback handling**: If `version.json` is missing (fresh clone before first build), `src/constants/defaults.ts` generates a fallback version from `package.json`
+
+### Version Display
+
+The version is displayed in the UI footer (bottom right) next to the GitHub repository link. The format is:
+- `0.2.1+a3f2b9c` (clean working directory)
+- `0.2.1+a3f2b9c-dirty` (uncommitted changes present)
+- `0.2.1-dev` (fallback when version.json is missing)
+
+### Files
+
+- `scripts/generate-version.js` - Generates version.json from git + package.json
+- `scripts/bump-version.js` - Manually bumps semver in package.json
+- `src/version.json` - Auto-generated, ignored by git
+- `src/version.json.template` - Fallback template (committed to repo)
+- `src/constants/defaults.ts` - Exports `APP_VERSION` and `BUILD_INFO`
+
 ## Initial Setup (Fresh Clone)
 
 ```sh