aichat: init (#7207)

aichat is an all in one CLI tool for AI interactions.
On first run it prompts you to create a config so I made a home manager module to do this declaratively.

tests/modules/programs/aichat/default.nix

@@ -0,0 +1,3 @@
+{
+  aichat-settings = ./settings.nix;
+}

tests/modules/programs/aichat/settings.nix

@@ -0,0 +1,26 @@
+{ ... }:
+{
+  programs.aichat = {
+    enable = true;
+    settings = {
+      model = "Ollama:mistral-small:latest";
+      clients = [
+        {
+          type = "openai-compatible";
+          name = "Ollama";
+          api_base = "http://localhost:11434/v1";
+          models = [
+            {
+              name = "llama3.2:latest";
+            }
+          ];
+        }
+      ];
+    };
+  };
+  nmt.script = ''
+    assertFileExists home-files/.config/aichat/config.yaml
+    assertFileContent home-files/.config/aichat/config.yaml \
+      ${./settings.yml}
+  '';
+}

tests/modules/programs/aichat/settings.yml

@@ -0,0 +1,7 @@
+clients:
+- api_base: http://localhost:11434/v1
+  models:
+  - name: llama3.2:latest
+  name: Ollama
+  type: openai-compatible
+model: Ollama:mistral-small:latest