refactor: add terminal output and forms package (#1124)

- `internal/terminal`: streams and the prompting policy, interactive forms (issue, PR, review, merge, milestone), editor / pager / browser launching, JSON and `--jq` output.
- An aligned table renderer and a record renderer for human output; both strip control and escape characters from server-supplied text so titles and bodies cannot inject terminal sequences.

Reviewed-on: https://gitea.com/gitea/tea/pulls/1124
Reviewed-by: TheFox0x7 <95654+thefox0x7@noreply.gitea.com>

internal/terminal/pull_form.go

@@ -0,0 +1,120 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package terminal
+
+import (
+	"context"
+	"strings"
+	"unicode"
+	"unicode/utf8"
+
+	"charm.land/huh/v2"
+)
+
+// PullFormChoices supplies defaults and selectable options for interactive PR create.
+type PullFormChoices struct {
+	BaseOwner, Base, HeadOwner, HeadBranch string
+	// Title and Body seed the form; Title applies only while HeadBranch is kept.
+	Title, Body          string
+	AllowMaintainerEdits bool
+	Assignees            []string
+	Milestones           []IssueMilestoneChoice
+	Labels               []IssueLabelChoice
+	CanPush              bool
+	EditBody             BodyEditor
+}
+
+// PullFormValues holds interactively collected pull request create fields.
+type PullFormValues struct {
+	IssueFormValues
+	Agit                 bool
+	Base, Head, Topic    string
+	AllowMaintainerEdits bool
+}
+
+// PullForm collects interactive pull create input.
+type PullForm interface {
+	CreatePull(context.Context, PullFormChoices) (PullFormValues, error)
+}
+
+// CreatePull runs the interactive pull create form on stderr.
+func (p *FormPrompter) CreatePull(ctx context.Context, choices PullFormChoices) (PullFormValues, error) {
+	agit, err := p.Confirm(ctx, "Do you want to create an agit flow pull request?")
+	if err != nil {
+		return PullFormValues{}, err
+	}
+
+	base := choices.Base
+	headOwner := choices.HeadOwner
+	headBranch := choices.HeadBranch
+	topic := headBranch
+	allowMaintainerEdits := choices.AllowMaintainerEdits
+
+	fields := []huh.Field{
+		huh.NewInput().Title("Target branch (required):").Value(&base).Validate(huh.ValidateNotEmpty()),
+	}
+	if agit {
+		fields = append(fields, huh.NewInput().Title("Topic branch (required):").Value(&topic).Validate(huh.ValidateNotEmpty()))
+	} else {
+		headField := huh.NewInput().Title("Source branch:").Value(&headBranch)
+		if strings.TrimSpace(headBranch) == "" {
+			headField = headField.Title("Source branch (required):").Validate(huh.ValidateNotEmpty())
+		}
+		fields = append(fields,
+			huh.NewInput().Title("Source repo owner:").Value(&headOwner),
+			headField,
+			huh.NewConfirm().Title("Allow maintainers to push to the source branch:").Value(&allowMaintainerEdits),
+		)
+	}
+	if err := p.runForm(ctx, huh.NewForm(huh.NewGroup(fields...))); err != nil {
+		return PullFormValues{}, err
+	}
+
+	title := DefaultPullTitle(headBranch)
+	if choices.Title != "" && headBranch == choices.HeadBranch {
+		title = choices.Title
+	}
+	// AGit pushes carry only a title and description.
+	properties, err := p.collectIssueProperties(ctx, title, choices.Body, IssueFormChoices{
+		Assignees: choices.Assignees, Milestones: choices.Milestones, Labels: choices.Labels, CanPush: choices.CanPush && !agit,
+		EditBody: choices.EditBody,
+	})
+	if err != nil {
+		return PullFormValues{IssueFormValues: properties}, err
+	}
+
+	headBranch = strings.TrimSpace(headBranch)
+	headOwner = strings.TrimSpace(headOwner)
+	head := headBranch
+	switch {
+	case agit && head == "":
+		head = "HEAD"
+	case !agit && headOwner != "" && headOwner != choices.BaseOwner:
+		head = headOwner + ":" + headBranch
+	}
+	return PullFormValues{
+		IssueFormValues:      properties,
+		Agit:                 agit,
+		Base:                 strings.TrimSpace(base),
+		Head:                 head,
+		Topic:                strings.TrimSpace(topic),
+		AllowMaintainerEdits: allowMaintainerEdits,
+	}, nil
+}
+
+// DefaultPullTitle turns a branch-like head into a readable pull title seed.
+func DefaultPullTitle(head string) string {
+	if i := strings.LastIndex(head, ":"); i != -1 {
+		head = head[i+1:]
+	}
+	parts := strings.Fields(strings.ToLower(strings.NewReplacer("_", " ", "-", " ").Replace(head)))
+	if len(parts) == 0 {
+		return ""
+	}
+	for i, part := range parts {
+		r, size := utf8.DecodeRuneInString(part)
+		parts[i] = string(unicode.ToUpper(r)) + part[size:]
+	}
+	return strings.Join(parts, " ")
+}