feat: initial m3ta-home structure

- flake.nix with nixpkgs, home-manager, nix-colors, m3ta-nixpkgs, agenix, NUR inputs
- lib/mkHome.nix: compose HM config from user + identity + context + sets
- profiles/base: shell, cli-tools, secrets (always loaded)
- profiles/contexts/desktop: WM, apps, theme, ghostty
- profiles/contexts/server: minimal headless
- profiles/sets/coding: core (git, direnv, jq, rg), editor, lsp, languages, agents
- profiles/sets/gaming: steam, gamescope, gpu
- profiles/sets/media: obs, ffmpeg, kdenlive, handbrake, yt-dlp
- users/m3tam3re/identities: private.nix, work.nix (git, jj, ssh per identity)
- users/m3tam3re/preferences: cliphist, difftastic, base packages

modules/default.nix

@@ -0,0 +1,33 @@
+# modules/default.nix — Export all m3ta-home modules as a HM module set.
+#
+# This allows nixos-config to import all modules at once:
+#   imports = [ inputs.m3ta-home.homeManagerModules.default ];
+#
+# Individual modules declare their own options (mkEnableOption etc.)
+# and are activated by mkHome's import mechanism.
+inputs: let
+  lib = inputs.nixpkgs.lib;
+
+  # Collect all .nix files recursively from a directory
+  collectModules = dir:
+    builtins.filterSource (path: _type:
+      lib.hasSuffix ".nix" (builtins.baseNameOf path))
+    dir;
+in {
+  default = {
+    imports = [
+      # Profiles
+      ./../profiles/base
+      ./../profiles/contexts/desktop
+      ./../profiles/contexts/server
+      ./../profiles/sets/coding
+      ./../profiles/sets/gaming
+      ./../profiles/sets/media
+
+      # Users
+      ./../users/m3tam3re/preferences
+      ./../users/m3tam3re/identities/private.nix
+      ./../users/m3tam3re/identities/work.nix
+    ];
+  };
+}