feat(issue): gh-style issue list, view, create, edit, close and reopen

issue list renders through the shared table: a context line, ID TITLE
LABELS [STATE] [KIND] AUTHOR UPDATED with relative times on a terminal,
the ID colored by state and linked, and a stable tab-separated column
set when piped; empty results say so on stderr. It gains -s -L -l -a -A
-m -S -w, @me, comma-separated label and milestone filters, and --web.

issue view, edit, close and reopen accept #N, OWNER/REPO#N and issue
URLs. Mutations report "✓ Created/Edited/Closed issue alice/x#5 (title)"
on a terminal; issue create prints the new issue's URL on stdout (also
as issue new), and close and reopen skip issues already in that state
with a ! line and take -c/--comment. issue create and edit gain the gh
short flags and singular --add-label, --remove-label, --add-assignee and
--remove-assignee (the plural names still work), and create gains --web.

The interactive create form asks for the title and body, then "What's
next?" (submit, add metadata or cancel), without a confirmation after
it; the edit form names the issue it edits. Every issue command has help
text with examples and completes its flags and issue numbers.

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

internal/app/args_test.go

@@ -85,8 +85,8 @@ func TestArgumentErrorsShowTheUsageLine(t *testing.T) {
 		args []string
 		want string
 	}{
-		{[]string{"issue", "view"}, "missing issue number\nUsage: tea issue view <number> [flags]\nRun 'tea issue view --help' for more information."},
-		{[]string{"issue", "view", "1", "2"}, "too many arguments\nUsage: tea issue view <number> [flags]"},
+		{[]string{"issue", "view"}, "missing issue number\nUsage: tea issue view {<number> | <url>} [flags]\nRun 'tea issue view --help' for examples."},
+		{[]string{"issue", "view", "1", "2"}, "too many arguments\nUsage: tea issue view {<number> | <url>} [flags]"},
 		{[]string{"issue", "list", "extra"}, "unexpected argument \"extra\"\nUsage: tea issue list [flags]"},
 		{[]string{"pr", "checkout"}, "missing pull request number\nUsage: tea pr checkout {<number> | <url> | <branch>} [flags]"},
 		{[]string{"run", "view"}, "missing run ID\nUsage: tea run view [<run-id>] [flags]"},