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

flake.nix

@@ -0,0 +1,43 @@
+{
+  description = "m3ta-home — portable user profiles and home-manager configurations";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+
+    home-manager = {
+      url = "github:nix-community/home-manager";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+
+    nix-colors.url = "github:misterio77/nix-colors";
+
+    m3ta-nixpkgs = {
+      url = "git+ssh://gitea@code.m3ta.dev/m3tam3re/m3ta-nixpkgs.git";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+
+    agenix.url = "github:ryantm/agenix";
+
+    nur.url = "github:nix-community/NUR";
+  };
+
+  outputs = {
+    self,
+    nixpkgs,
+    ...
+  } @ inputs: let
+    lib = nixpkgs.lib;
+  in {
+    # Home-Manager modules — import in nixos-config via:
+    #   imports = [ inputs.m3ta-home.homeManagerModules.default ];
+    homeManagerModules = import ./modules inputs;
+
+    # Library functions — use in nixos-config via:
+    #   m3ta-lib = inputs.m3ta-home.lib;
+    #   imports = [ (m3ta-lib.mkHome { ... }) ];
+    lib = import ./lib {inherit inputs;};
+
+    # Overlays (re-exports from m3ta-nixpkgs)
+    overlays = inputs.m3ta-nixpkgs.overlays;
+  };
+}