feat: add notesmd-cli package and flake checks

- Add notesmd-cli package for Obsidian CLI interaction
- Add flake checks for package build verification
- Add documentation for notesmd-cli, sidecar, and td
- Update AGENTS.md to reference td instead of beads
- Format pkgs/default.nix with proper braces

docs/packages/notesmd-cli.md

@@ -0,0 +1,117 @@
+# notesmd-cli
+
+Obsidian CLI (Community) - Interact with Obsidian in the terminal.
+
+## Description
+
+notesmd-cli is a command-line interface for interacting with Obsidian, the popular knowledge management and note-taking application. It allows you to create, search, and manipulate notes directly from the terminal.
+
+## Features
+
+- 📝 **Note Creation**: Create new notes from the command line
+- 🔍 **Search**: Search through your Obsidian vault
+- 📂 **Vault Management**: Interact with your vault structure
+- 🔗 **WikiLink Support**: Work with Obsidian's WikiLink format
+- 🏷️ **Tag Support**: Manage and search by tags
+- ⚡ **Fast**: Lightweight Go binary with no external dependencies
+
+## Installation
+
+### Via Overlay
+
+```nix
+{pkgs, ...}: {
+  environment.systemPackages = with pkgs; [
+    notesmd-cli
+  ];
+}
+```
+
+### Direct Reference
+
+```nix
+{pkgs, ...}: {
+  environment.systemPackages = with pkgs; [
+    inputs.m3ta-nixpkgs.packages.${pkgs.system}.notesmd-cli
+  ];
+}
+```
+
+### Run Directly
+
+```bash
+nix run git+https://code.m3ta.dev/m3tam3re/nixpkgs#notesmd-cli
+```
+
+## Usage
+
+### Basic Commands
+
+```bash
+# Show help
+notesmd-cli --help
+
+# Create a new note
+notesmd-cli new "My Note Title"
+
+# Search notes
+notesmd-cli search "search term"
+
+# List notes
+notesmd-cli list
+```
+
+### Working with Vaults
+
+```bash
+# Specify vault path
+notesmd-cli --vault /path/to/vault new "Note Title"
+
+# Open a note in Obsidian
+notesmd-cli open "Note Name"
+```
+
+### Advanced Usage
+
+```bash
+# Search with tags
+notesmd-cli search --tag "project"
+
+# Append to existing note
+notesmd-cli append "Note Name" "Additional content"
+```
+
+## Configuration
+
+### Environment Variables
+
+- `OBSIDIAN_VAULT`: Default vault path
+
+### Command Line Options
+
+Run `notesmd-cli --help` for a complete list of options.
+
+## Build Information
+
+- **Version**: 0.3.0
+- **Language**: Go
+- **License**: MIT
+- **Source**: [GitHub](https://github.com/Yakitrak/notesmd-cli)
+- **Vendor Hash**: null (no external dependencies)
+
+## Platform Support
+
+- Linux
+- macOS (Unix systems)
+
+## Notes
+
+- No vendor dependencies (pure Go stdlib)
+- The binary is named `notesmd-cli` (not `notesmd`)
+- This is the community CLI, not the official Obsidian CLI
+
+## Related
+
+- [Obsidian](https://obsidian.md) - The Obsidian application
+- [Adding Packages](../guides/adding-packages.md) - How to add new packages
+- [Quick Start](../QUICKSTART.md) - Getting started guide