Add agentpr issue create/comment/edit

Filing an issue as unkin-agent means hand-rolling a POST to the issues
API with a manually minted token, the exact credential handling agentpr
exists to encapsulate.

- add `issue create`, `issue comment` and `issue edit`, mirroring the pr
  command group's flags, output and errors
- add CreateIssue/EditIssue to the Gitea client, sharing EditOptions with
  EditPR
- build both comment commands from one constructor so pr and issue
  comments cannot drift off Gitea's shared endpoint
- cover create, edit, a missing repo, an API error and missing flags

cmd/agentpr/main_test.go

@@ -4,6 +4,8 @@ import (
 	"io"
 	"strings"
 	"testing"
+
+	"github.com/spf13/cobra"
 )
 
 // A malformed --repo must fail the command (so main exits non-zero). ParseRepo
@@ -49,3 +51,101 @@ func TestPREditRejectsEmptyTitle(t *testing.T) {
 		t.Errorf("error = %q, want it to reject the empty title", err)
 	}
 }
+
+// execute runs the command tree with args, discarding output, so tests assert
+// on the error alone. Every case here fails before any Vault/Gitea call.
+func execute(args ...string) error {
+	cmd := newRootCmd()
+	cmd.SetArgs(args)
+	cmd.SetOut(io.Discard)
+	cmd.SetErr(io.Discard)
+	return cmd.Execute()
+}
+
+// An issue needs a title; Gitea rejects an empty one, so the command must too.
+func TestIssueCreateRequiresTitle(t *testing.T) {
+	err := execute("issue", "create", "--repo", "unkin/repo", "--body", "b")
+	if err == nil {
+		t.Fatal("Execute() = nil, want an error when --title is missing")
+	}
+	if !strings.Contains(err.Error(), "--title is required") {
+		t.Errorf("error = %q, want it to name the missing flag", err)
+	}
+}
+
+// --repo is required, and cobra must reject its absence before anything reaches
+// for a token.
+func TestIssueCreateRequiresRepo(t *testing.T) {
+	err := execute("issue", "create", "--title", "t")
+	if err == nil {
+		t.Fatal("Execute() = nil, want an error when --repo is missing")
+	}
+	if !strings.Contains(err.Error(), "repo") {
+		t.Errorf("error = %q, want it to name the missing flag", err)
+	}
+}
+
+func TestIssueCreateBadRepoErrors(t *testing.T) {
+	if err := execute("issue", "create", "--repo", "not-a-repo", "--title", "t"); err == nil {
+		t.Fatal("Execute() = nil, want error for a malformed --repo")
+	}
+}
+
+// `issue comment` addresses the issue by --issue, not --pr, and needs it.
+func TestIssueCommentRequiresIssueNumber(t *testing.T) {
+	err := execute("issue", "comment", "--repo", "unkin/repo", "--body", "hi")
+	if err == nil {
+		t.Fatal("Execute() = nil, want an error when --issue is missing")
+	}
+	if !strings.Contains(err.Error(), "issue") {
+		t.Errorf("error = %q, want it to name the missing --issue flag", err)
+	}
+}
+
+func TestIssueEditRequiresTitleOrBody(t *testing.T) {
+	err := execute("issue", "edit", "--repo", "unkin/repo", "--issue", "12")
+	if err == nil {
+		t.Fatal("Execute() = nil, want an error when neither --title nor --body is given")
+	}
+	if !strings.Contains(err.Error(), "--title or --body") {
+		t.Errorf("error = %q, want it to name the missing flags", err)
+	}
+}
+
+func TestIssueEditRejectsEmptyTitle(t *testing.T) {
+	err := execute("issue", "edit", "--repo", "unkin/repo", "--issue", "12", "--title", "")
+	if err == nil {
+		t.Fatal("Execute() = nil, want an error for an empty --title")
+	}
+	if !strings.Contains(err.Error(), "--title cannot be empty") {
+		t.Errorf("error = %q, want it to reject the empty title", err)
+	}
+}
+
+// PRs and issues share Gitea's comment endpoint, so both comment commands are
+// built from one constructor: they must stay identical apart from the flag
+// naming the number.
+func TestCommentCommandsStayInStep(t *testing.T) {
+	find := func(group string) *cobra.Command {
+		t.Helper()
+		cmd, _, err := newRootCmd().Find([]string{group, "comment"})
+		if err != nil || cmd.Name() != "comment" {
+			t.Fatalf("%s comment not found: %v", group, err)
+		}
+		return cmd
+	}
+	has := func(cmd *cobra.Command, name string) bool { return cmd.Flags().Lookup(name) != nil }
+
+	prCmd, issueCmd := find("pr"), find("issue")
+	for _, name := range []string{"repo", "body"} {
+		if !has(prCmd, name) || !has(issueCmd, name) {
+			t.Errorf("--%s missing: pr=%t issue=%t", name, has(prCmd, name), has(issueCmd, name))
+		}
+	}
+	if !has(prCmd, "pr") || has(prCmd, "issue") {
+		t.Error("pr comment must take --pr and only --pr")
+	}
+	if !has(issueCmd, "issue") || has(issueCmd, "pr") {
+		t.Error("issue comment must take --issue and only --issue")
+	}
+}