feat: migrate from nodeenv to bunenv for Bun environment management

Replace nodeenv with bunenv for frontend tooling isolation:

**Changes:**
- Makefile: Replace `nodeenv --python-virtualenv` with `bunenv --python-virtualenv --bun=latest`
- pyproject.toml: Add `bunenv>=0.1.0` to dev dependencies
- uv.lock: Update lock file with bunenv dependency

**Benefits:**
✅ Purpose-built for Bun (vs Node.js-focused nodeenv)
✅ Maintained actively with modern tooling
✅ GitHub Releases API integration (vs nodejs.org index)
✅ Same proven architecture as nodeenv
✅ Zero breaking changes to workflow

**Testing:**
Verified bunenv 0.1.0 installs correctly via `uv sync --group dev`

**Migration Path:**
`nodeenv --python-virtualenv` → `bunenv --python-virtualenv --bun=latest`

No other changes required - bunenv provides the same isolation
and activation mechanism, just optimized for Bun.

Related: JacobCoffee/bunenv#7 (bunenv GitHub Action)

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

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

Author: JacobCoffee

Makefile

@@ -53,7 +53,7 @@ install-prek: ## Install prek and install hooks
 .PHONY: install-frontend
 install-frontend: ## Install the frontend dependencies
 	@echo "=> Installing frontend dependencies"
-	@nodeenv --python-virtualenv
+	@bunenv --python-virtualenv --bun=latest
 	@bun install
 	@echo "=> Frontend dependencies installed"
 

pyproject.toml

@@ -38,6 +38,7 @@ dev = [
     "codespell>=2.2.6",
     "prek>=0.2.18",
     "pytailwindcss>=0.2.0",
+    "bunenv>=0.1.0",
     "sourcery>=1.14.0",
     "ty>=0.0.1a26",
     "aiosqlite>=0.21.0",