feat: first version of bot (#2)

### Explanation

This should set up everything we need for our initial launch. Test coverage is at 100% to ensure nothing breaks.

### Issue

_No response_

### Attestations

- [x] I have read and agree to the [Code of Conduct](https://docs.nhcarrigan.com/community/coc/)
- [x] I have read and agree to the [Community Guidelines](https://docs.nhcarrigan.com/community/guide/).
- [x] My contribution complies with the [Contributor Covenant](https://docs.nhcarrigan.com/dev/covenant/).

### Dependencies

- [x] I have pinned the dependencies to a specific patch version.

### Style

- [x] I have run the linter and resolved any errors.
- [x] My pull request uses an appropriate title, matching the conventional commit standards.
- [x] My scope of feat/fix/chore/etc. correctly matches the nature of changes in my pull request.

### Tests

- [x] My contribution adds new code, and I have added tests to cover it.
- [ ] My contribution modifies existing code, and I have updated the tests to reflect these changes.
- [x] All new and existing tests pass locally with my changes.
- [x] Code coverage remains at or above the configured threshold.

### Documentation

Coming soon - I'm working on the infra for docs next

### Versioning

Major - My pull request introduces a breaking change.

Reviewed-on: https://codeberg.org/nhcarrigan/rig-task-bot/pulls/2
Co-authored-by: Naomi Carrigan <commits@nhcarrigan.com>
Co-committed-by: Naomi Carrigan <commits@nhcarrigan.com>

test/modules/defaultCommand.spec.ts

@@ -0,0 +1,24 @@
+/**
+ * @copyright nhcarrigan
+ * @license Naomi's Public License
+ * @author Naomi Carrigan
+ */
+
+import { describe, it, expect, vi } from "vitest";
+import { defaultCommand } from "../../src/modules/defaultCommand.js";
+
+describe("defaultCommand", () => {
+  it("should respond with expected values", async() => {
+    expect.assertions(1);
+    const mockInteraction = {
+      commandName: "test",
+      reply:       vi.fn(),
+    };
+    await defaultCommand({} as never, mockInteraction as never);
+    expect(mockInteraction.reply, "should reply with correct body").
+      toHaveBeenCalledWith({
+        content:   "Interaction test not found.",
+        ephemeral: true,
+      });
+  });
+});