feat(milestone): milestone tables, views, forms and one selection model

milestone view printed the list row, and milestone list hid the due date
and progress. milestone list now shows ID TITLE [STATE] DUE PROGRESS, open
milestones first and by due date; milestone view shows the state, due
date, progress, description and the milestone's web page (also --web).

Every milestone command addresses milestones by title or ID. Mutations
report ✓ lines: milestone create also prints the new milestone's URL and
takes the title as an argument; close and reopen skip milestones already
in that state; delete names the milestone in its confirmation; milestone
issue add and remove report one line such as "✓ Added #1, #2 to
milestone "v1.0" in alice/x". milestone issue list uses the issue table.
milestone edit without flags on a terminal opens the milestone form with
the current values, and every milestone command completes milestone
titles and has help text with examples.

Signed-off-by: bircni <bircni@icloud.com>

internal/terminal/milestone_form_test.go

@@ -5,14 +5,26 @@ package terminal
 
 import (
 	"context"
+	"strings"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/require"
 )
 
 func TestMilestoneFormMarksTitleRequired(t *testing.T) {
 	p, rendered := accessiblePrompter(t, "v1\n\n\n")
-	_, err := p.CreateMilestone(context.Background())
+	_, err := p.EditMilestone(context.Background(), "", MilestoneFormValues{})
 	require.NoError(t, err)
 	require.Contains(t, rendered.String(), "Milestone title (required):")
 }
+
+func TestMilestoneFormStartsFromCurrentValues(t *testing.T) {
+	due := time.Date(2026, 12, 31, 0, 0, 0, 0, time.UTC)
+	p, _ := testPrompter(strings.NewReader("\r\r\r"))
+	values, err := p.EditMilestone(context.Background(), "Editing milestone v1.0", MilestoneFormValues{Title: "v1.0", Description: "First", Deadline: &due})
+	require.NoError(t, err)
+	require.Equal(t, "v1.0", values.Title)
+	require.Equal(t, "First", values.Description)
+	require.Equal(t, due, *values.Deadline)
+}