feat(tools): issue_get, release_create, repo_delete (#11, #17, #20)

issue_get: GET /repos/{owner}/{repo}/issues/{number} — full issue with labels, assignees, comment count
release_create: POST /repos/{owner}/{repo}/releases — create release and tag in one call
repo_delete: DELETE /repos/{owner}/{repo} — confirm=<repo name> required, blocks accidents

internal/gitea/issues_test.go

@@ -45,6 +45,37 @@ func TestCreateIssue(t *testing.T) {
 	assert.Equal(t, "open", iss.State)
 }
 
+func TestGetIssue(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		assert.Equal(t, http.MethodGet, r.Method)
+		assert.Equal(t, "/api/v1/repos/o/r/issues/42", r.URL.Path)
+		w.Header().Set("Content-Type", "application/json")
+		_, _ = w.Write([]byte(`{"number":42,"title":"fix auth","body":"details","state":"open","html_url":"http://example.com/issues/42","created_at":"2026-05-01T00:00:00Z","updated_at":"2026-05-02T00:00:00Z","comments":3}`))
+	}))
+	defer srv.Close()
+
+	c := gitea.NewClient(srv.URL, "tok")
+	iss, err := c.GetIssue(context.Background(), "o", "r", 42)
+	require.NoError(t, err)
+	assert.Equal(t, 42, iss.Number)
+	assert.Equal(t, "fix auth", iss.Title)
+	assert.Equal(t, "open", iss.State)
+	assert.Equal(t, 3, iss.Comments)
+}
+
+func TestGetIssue_NotFound(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusNotFound)
+		_, _ = w.Write([]byte(`{"message":"issue not found"}`))
+	}))
+	defer srv.Close()
+
+	c := gitea.NewClient(srv.URL, "tok")
+	_, err := c.GetIssue(context.Background(), "o", "r", 999)
+	require.Error(t, err)
+	assert.ErrorIs(t, err, gitea.ErrNotFound)
+}
+
 func TestCreateIssueComment(t *testing.T) {
 	var captured []byte
 	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {