feat: major dotfiles refactor with documentation and multi-platform improvements

- Add comprehensive CLAUDE.md with chezmoi best practices and AI assistant guidelines
- Restructure TODO.md with prioritized tasks and detailed organization
- Add PowerShell profile template for Windows platform support
- Split git configs into identity-specific templates (ryan/xevion)
- Convert nushell env.nu and gitconfig to templates for cross-platform rendering
- Refactor chezmoi hooks to TypeScript (.init_pre.ts, .update_pre.ts)
- Update .chezmoiignore with better platform-specific file handling
- Remove deprecated shellchecker.sh and tasks.json from VS Code config
- Add mise integration to shell configs (bash, zsh, nushell, PowerShell)
- Clean up commonrc.sh.tmpl WSL-specific code
- Disable Deno in VS Code settings, enable simple dialog mode
- Add nushell extension recommendation to VS Code

This commit establishes better cross-platform support (Windows/WSL/Linux),
improves documentation for future maintenance, and standardizes configuration
management patterns across the repository.

home/hooks/.update_pre.ts

@@ -0,0 +1,19 @@
+#!/usr/bin/env bun
+
+// chezmoi update --init does not invoke the 'hooks.init.pre' hook, so we do it ourselves
+const chezmoiArgs = process.env.CHEZMOI_ARGS || '';
+
+if (chezmoiArgs.includes('init')) {
+    // CHEZMOI_UPDATE is just a hint in case we need to know if we're updating
+    const scriptDir = import.meta.dir;
+    const initPreScript = `${scriptDir}/.init_pre.ts`;
+
+    await Bun.spawn(['bun', initPreScript], {
+        env: {
+            ...process.env,
+            CHEZMOI_UPDATE: '1'
+        },
+        stdout: 'inherit',
+        stderr: 'inherit'
+    });
+}