feat: add issue delete, pin, and unpin (task 0006)

Add the remaining simple issue mutations. `issue delete` hard-deletes via
the DELETE endpoint and is deliberately not idempotent — a nonexistent
issue yields ISSUE_NOT_FOUND rather than reporting success. `issue pin`
and `issue unpin` read the current pin state (Gitea's pin_order field) and
short-circuit to an idempotent no-op with an Already pinned/unpinned
message when there is nothing to do.

test/issue-pin.test.ts

@@ -0,0 +1,96 @@
+import { afterEach, describe, expect, it } from "vitest";
+import { startFixtureServer, type FixtureServer } from "./fixture-server.js";
+import { runCliTest, testModeEnv } from "./harness.js";
+
+const ISSUE_PATH = "/api/v1/repos/testowner/testrepo/issues/7";
+const PIN_PATH = "/api/v1/repos/testowner/testrepo/issues/7/pin";
+
+let server: FixtureServer;
+
+afterEach(async () => {
+  await server.close();
+});
+
+describe("issue pin", () => {
+  it("pins an unpinned issue and reports the pinned state", async () => {
+    server = await startFixtureServer([
+      { method: "GET", path: ISSUE_PATH, body: { number: 7, state: "open" } },
+      { method: "POST", path: PIN_PATH, status: 204 },
+    ]);
+    const { stdout, exitCode } = await runCliTest(["issue", "pin", "7"], {
+      env: testModeEnv(server.url),
+    });
+
+    expect(exitCode).toBe(0);
+    expect(stdout).toContain("issue:");
+    expect(stdout).toContain("number: 7");
+    expect(stdout).toContain("state: open");
+    expect(stdout).toContain("pinned: true");
+    expect(server.requests.some((request) => request.method === "POST")).toBe(true);
+  });
+
+  it("returns early with Already pinned on an already-pinned issue", async () => {
+    server = await startFixtureServer([
+      { method: "GET", path: ISSUE_PATH, body: { number: 7, state: "open", pin_order: 1 } },
+    ]);
+    const { stdout, exitCode } = await runCliTest(["issue", "pin", "7"], {
+      env: testModeEnv(server.url),
+    });
+
+    expect(exitCode).toBe(0);
+    expect(stdout).toContain("message: Already pinned");
+    expect(server.requests.some((request) => request.method === "POST")).toBe(false);
+  });
+
+  it("prints help with --help without calling the API", async () => {
+    server = await startFixtureServer([]);
+    const { stdout, exitCode } = await runCliTest(["issue", "pin", "--help"], {
+      env: testModeEnv(server.url),
+    });
+
+    expect(exitCode).toBe(0);
+    expect(stdout).toContain("usage: gitea-axi issue pin");
+    expect(server.requests).toHaveLength(0);
+  });
+});
+
+describe("issue unpin", () => {
+  it("unpins a pinned issue and reports the unpinned state", async () => {
+    server = await startFixtureServer([
+      { method: "GET", path: ISSUE_PATH, body: { number: 7, state: "open", pin_order: 1 } },
+      { method: "DELETE", path: PIN_PATH, status: 204 },
+    ]);
+    const { stdout, exitCode } = await runCliTest(["issue", "unpin", "7"], {
+      env: testModeEnv(server.url),
+    });
+
+    expect(exitCode).toBe(0);
+    expect(stdout).toContain("number: 7");
+    expect(stdout).toContain("pinned: false");
+    expect(server.requests.some((request) => request.method === "DELETE")).toBe(true);
+  });
+
+  it("returns early with Already unpinned on an issue that is not pinned", async () => {
+    server = await startFixtureServer([
+      { method: "GET", path: ISSUE_PATH, body: { number: 7, state: "open" } },
+    ]);
+    const { stdout, exitCode } = await runCliTest(["issue", "unpin", "7"], {
+      env: testModeEnv(server.url),
+    });
+
+    expect(exitCode).toBe(0);
+    expect(stdout).toContain("message: Already unpinned");
+    expect(server.requests.some((request) => request.method === "DELETE")).toBe(false);
+  });
+
+  it("prints help with --help without calling the API", async () => {
+    server = await startFixtureServer([]);
+    const { stdout, exitCode } = await runCliTest(["issue", "unpin", "--help"], {
+      env: testModeEnv(server.url),
+    });
+
+    expect(exitCode).toBe(0);
+    expect(stdout).toContain("usage: gitea-axi issue unpin");
+    expect(server.requests).toHaveLength(0);
+  });
+});