feat!: rebuild tea on Cobra with explicit noun/verb commands (#1126)

- **switch tea to the Cobra command tree:** `internal/app` wires the packages from parts 1–4 into explicit noun/verb commands with `--repo`, `--json` / `--jq`, `--sudo` and `--debug`; `main.go` points at it. Build, release and docs tooling (`tools/cli-docs`, Makefile, goreleaser, snap, CI) and README / CONTRIBUTING are updated.
- **remove the urfave/cli command tree:** deletes `cmd/`, `modules/`, the old integration tests, contrib completion scripts and the generated `docs/CLI.md`, and drops their dependencies. This commit only deletes.

## Breaking changes

This is a breaking release. It requires Gitea 28 or newer; configuration moves to separate `config.yml` and `hosts.yml` files and requires fresh authentication, and command names, aliases, flags and output formats change. `docs/migration-1.0.md` maps every old command, flag and environment variable to its replacement.

## Issues

fixes #1118
fixes #1116
fixes #1115
fixes #1094
fixes #1091
fixes #1073
fixes #1052
fixes #1032
fixes #1023
fixes #966
fixes #908
fixes #833
fixes #831
fixes #817
fixes #804
fixes #779
fixes #770
fixes #737
fixes #697
fixes #726
fixes #677
fixes #672
fixes #633
fixes #632
fixes #560
fixes #556
fixes #523
fixes #516
fixes #510
fixes #504
fixes #500
fixes #482
fixes #406
fixes #403
fixes #373
fixes #351
fixes #344
fixes #326
fixes #325
fixes #323
fixes #246
fixes #240
fixes #232
fixes #197
fixes #172
fixes #141
fixes #69
fixes #1110
fixes #569
fixes #480
fixes #666
fixes #670
fixes #457
fixes #643
fixes #498
fixes #490
fixes #1069
fixes #834
fixes #602
fixes #328
fixes #417
fixes #571
fixes #1029
fixes #489
fixes #1050
fixes #162
fixes #430
fixes #1087
fixes #683

Reviewed-on: https://gitea.com/gitea/tea/pulls/1126
Reviewed-by: TheFox0x7 <95654+thefox0x7@noreply.gitea.com>

modules/theme/background.go

@@ -1,31 +0,0 @@
-// Copyright 2026 The Gitea Authors. All rights reserved.
-// SPDX-License-Identifier: MIT
-
-package theme
-
-import (
-	"os"
-
-	"charm.land/lipgloss/v2"
-	"golang.org/x/term"
-)
-
-// defaultDarkBackground is the background to assume when we cannot detect one. It
-// matches the default lipgloss falls back to.
-const defaultDarkBackground = true
-
-// HasDarkBackground reports whether the terminal has a dark background.
-//
-// It only asks the terminal when stdin and stdout are both terminals. Detection
-// works by writing an escape sequence to the output and waiting for the terminal
-// to answer on the input, and nothing answers when stdio is redirected, so asking
-// means waiting on a reply that never comes. On Windows that wait is unbounded:
-// lipgloss opens the console directly rather than giving up, which is why tea used
-// to hang at start-up under a service or a CI runner.
-func HasDarkBackground() bool {
-	if !term.IsTerminal(int(os.Stdin.Fd())) || !term.IsTerminal(int(os.Stdout.Fd())) {
-		return defaultDarkBackground
-	}
-
-	return lipgloss.HasDarkBackground(os.Stdin, os.Stdout)
-}