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

README.md

@@ -47,11 +47,14 @@ nix run git+https://code.m3ta.dev/m3tam3re/nixpkgs#zellij-ps
 | `mem0`             | AI memory assistant with vector storage |
 | `msty-studio`      | Msty Studio application               |
 | `n8n`              | Free and source-available fair-code licensed workflow automation tool |
+| `notesmd-cli`      | Obsidian CLI (Community) - Interact with Obsidian in the terminal |
 | `opencode`         | AI coding agent built for the terminal |
 | `opencode-desktop` | OpenCode Desktop App with Wayland support (includes workaround for upstream issue #11755) |
 | `pomodoro-timer`   | Pomodoro timer utility                |
 | `rofi-project-opener` | Rofi-based project launcher        |
+| `sidecar`          | Companion tool for CLI agents with diffs, file trees, and task management |
 | `stt-ptt`          | Push to Talk Speech to Text           |
+| `td`               | Minimalist CLI for tracking tasks across AI coding sessions |
 | `tuxedo-backlight` | Backlight control for Tuxedo laptops  |
 | `zellij-ps`        | Project switcher for Zellij           |