refactor: reorganize, add package (opencode, osgrep, beads), add ai agent shell

modules/home/devtools/opencode.nix

@@ -0,0 +1,107 @@
+{ config, lib, pkgs, customPkgs, ... }:
+let
+  inherit (lib) mkEnableOption mkOption types mkIf;
+  cfg = config.rsydn.opencode;
+
+  # Build the config JSON, filtering out null/empty values
+  opencodeConfig = lib.filterAttrs (_: v: v != null && v != { }) {
+    "$schema" = "https://opencode.ai/config.json";
+    theme = cfg.theme;
+    model = cfg.model;
+    small_model = cfg.smallModel;
+    autoupdate = false; # Nix manages updates
+    mcp = if cfg.mcpServers != { } then cfg.mcpServers else null;
+    keybinds = if cfg.keybinds != { } then cfg.keybinds else null;
+  };
+in {
+  options.rsydn.opencode = {
+    enable = mkEnableOption "OpenCode CLI with managed configuration";
+
+    package = mkOption {
+      type = types.nullOr types.package;
+      default = customPkgs.opencode;
+      description = ''
+        OpenCode package to use. Defaults to the custom-built package
+        from packages/opencode.nix via customPkgs.
+      '';
+    };
+
+    theme = mkOption {
+      type = types.str;
+      default = "catppuccin";
+      description = "UI theme for OpenCode TUI";
+    };
+
+    model = mkOption {
+      type = types.str;
+      default = "anthropic/claude-sonnet-4-5";
+      description = "Primary LLM model identifier";
+    };
+
+    smallModel = mkOption {
+      type = types.str;
+      default = "anthropic/claude-haiku-3-5";
+      description = "Lightweight model for tasks like title generation";
+    };
+
+    mcpServers = mkOption {
+      type = types.attrs;
+      default = { };
+      example = {
+        nixos = {
+          type = "stdio";
+          command = "uvx";
+          args = [ "mcp-nixos" ];
+        };
+      };
+      description = "MCP server configurations";
+    };
+
+    keybinds = mkOption {
+      type = types.attrs;
+      default = { };
+      description = "Custom keybinding overrides";
+    };
+
+    # Future extension points (joelhooks-style)
+    agents = mkOption {
+      type = types.attrsOf types.path;
+      default = { };
+      description = ''
+        Custom agent markdown files.
+        Keys become filenames under ~/.config/opencode/agent/
+      '';
+    };
+
+    commands = mkOption {
+      type = types.attrsOf types.path;
+      default = { };
+      description = ''
+        Custom command markdown files.
+        Keys become filenames under ~/.config/opencode/command/
+      '';
+    };
+
+    extraConfig = mkOption {
+      type = types.attrs;
+      default = { };
+      description = "Additional config options to merge into opencode.json";
+    };
+  };
+
+  config = mkIf cfg.enable {
+    home.packages = lib.optional (cfg.package != null) cfg.package;
+
+    xdg.configFile = {
+      # Global config file
+      "opencode/opencode.json".text =
+        builtins.toJSON (opencodeConfig // cfg.extraConfig);
+    } // lib.mapAttrs' (name: path:
+      # Agent markdown files
+      lib.nameValuePair "opencode/agent/${name}.md" { source = path; })
+      cfg.agents // lib.mapAttrs' (name: path:
+        # Command markdown files
+        lib.nameValuePair "opencode/command/${name}.md" { source = path; })
+      cfg.commands;
+  };
+}