feat(pulls): add edit subcommand for pull requests (#944)

## Summary

- Add `tea pr edit` subcommand to support editing pull request properties (description, title, milestone, deadline, assignees, labels, reviewers)
- Add `--add-reviewers` / `--remove-reviewers` flags for managing PR reviewers via `CreateReviewRequests` / `DeleteReviewRequests` API
- Extract shared helpers (`ResolveLabelOpts`, `ApplyLabelChanges`, `ApplyReviewerChanges`, `ResolveMilestoneID`) into `modules/task/labels.go` to reduce duplication between issue and PR editing
- Refactor existing `EditIssue` to use the same shared helpers
- Wrap original error in `ResolveMilestoneID` to preserve underlying error context

## Usage

```bash
# Edit PR description
tea pr edit 1 --description "new description"

# Edit PR title
tea pr edit 1 --title "new title"

# Edit multiple fields
tea pr edit 1 --title "new title" --description "new desc" --add-labels "bug"

# Edit multiple PRs
tea pr edit 1 2 3 --add-assignees "user1"

# Add reviewers
tea pr edit 1 --add-reviewers "user1,user2"

# Remove reviewers
tea pr edit 1 --remove-reviewers "user1"
```

## Test plan

- [x] `go build .` succeeds
- [x] `go test ./...` passes
- [x] `make clean && make vet && make lint && make fmt-check && make docs-check && make build` all pass
- [x] `tea pr edit <idx> --description "test"` updates PR description on a Gitea instance
- [x] `tea pr edit <idx> --title "test"` updates PR title
- [x] `tea pr edit <idx> --add-labels "bug"` adds label
- [x] `tea pr edit <idx> --add-reviewers "user"` requests review
- [x] `tea pr edit <idx> --remove-reviewers "user"` removes reviewer
- [x] Existing `tea issues edit` still works correctly after refactor

Reviewed-on: https://gitea.com/gitea/tea/pulls/944
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: appleboy <appleboy.tw@gmail.com>
Co-committed-by: appleboy <appleboy.tw@gmail.com>

cmd/pulls.go

@@ -72,6 +72,7 @@ var CmdPulls = cli.Command{
 		&pulls.CmdPullsCreate,
 		&pulls.CmdPullsClose,
 		&pulls.CmdPullsReopen,
+		&pulls.CmdPullsEdit,
 		&pulls.CmdPullsReview,
 		&pulls.CmdPullsApprove,
 		&pulls.CmdPullsReject,

cmd/pulls/edit.go

@@ -6,15 +6,86 @@ package pulls
 import (
 	stdctx "context"
 	"fmt"
+	"strings"
 
+	"code.gitea.io/tea/cmd/flags"
 	"code.gitea.io/tea/modules/context"
 	"code.gitea.io/tea/modules/print"
+	"code.gitea.io/tea/modules/task"
 	"code.gitea.io/tea/modules/utils"
 
 	"code.gitea.io/sdk/gitea"
 	"github.com/urfave/cli/v3"
 )
 
+// CmdPullsEdit is the subcommand of pulls to edit pull requests
+var CmdPullsEdit = cli.Command{
+	Name:    "edit",
+	Aliases: []string{"e"},
+	Usage:   "Edit one or more pull requests",
+	Description: `Edit one or more pull requests. To unset a property again,
+use an empty string (eg. --milestone "").`,
+	ArgsUsage: "<idx> [<idx>...]",
+	Action:    runPullsEdit,
+	Flags: append(flags.IssuePREditFlags,
+		&cli.StringFlag{
+			Name:    "add-reviewers",
+			Aliases: []string{"r"},
+			Usage:   "Comma-separated list of usernames to request review from",
+		},
+		&cli.StringFlag{
+			Name:  "remove-reviewers",
+			Usage: "Comma-separated list of usernames to remove from reviewers",
+		},
+	),
+}
+
+func runPullsEdit(_ stdctx.Context, cmd *cli.Command) error {
+	ctx, err := context.InitCommand(cmd)
+	if err != nil {
+		return err
+	}
+	if err := ctx.Ensure(context.CtxRequirement{RemoteRepo: true}); err != nil {
+		return err
+	}
+
+	if !cmd.Args().Present() {
+		return fmt.Errorf("must specify at least one pull request index")
+	}
+
+	opts, err := flags.GetIssuePREditFlags(ctx)
+	if err != nil {
+		return err
+	}
+
+	if cmd.IsSet("add-reviewers") {
+		opts.AddReviewers = strings.Split(cmd.String("add-reviewers"), ",")
+	}
+	if cmd.IsSet("remove-reviewers") {
+		opts.RemoveReviewers = strings.Split(cmd.String("remove-reviewers"), ",")
+	}
+
+	indices, err := utils.ArgsToIndices(ctx.Args().Slice())
+	if err != nil {
+		return err
+	}
+
+	client := ctx.Login.Client()
+	for _, opts.Index = range indices {
+		pr, err := task.EditPull(ctx, client, *opts)
+		if err != nil {
+			return err
+		}
+		if ctx.Args().Len() > 1 {
+			fmt.Println(pr.HTMLURL)
+		} else {
+			print.PullDetails(pr, nil, nil)
+		}
+	}
+
+	return nil
+}
+
 // editPullState abstracts the arg parsing to edit the given pull request
 func editPullState(_ stdctx.Context, cmd *cli.Command, opts gitea.EditPullRequestOption) error {
 	ctx, err := context.InitCommand(cmd)