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/git/backend.go

@@ -1,103 +0,0 @@
-// Copyright 2026 The Gitea Authors. All rights reserved.
-// SPDX-License-Identifier: MIT
-
-package git
-
-import (
-	"fmt"
-	"sort"
-	"sync"
-)
-
-var backendRegistry = struct {
-	sync.RWMutex
-	current  string
-	backends map[string]Backend
-}{
-	backends: make(map[string]Backend),
-}
-
-func init() {
-	mustRegisterBackend(cliBackend{})
-	mustUseBackend("cli")
-}
-
-// RegisterBackend makes a git backend available for later switching.
-func RegisterBackend(backend Backend) error {
-	if backend == nil {
-		return fmt.Errorf("git backend is nil")
-	}
-	name := backend.Name()
-	if name == "" {
-		return fmt.Errorf("git backend name is empty")
-	}
-
-	backendRegistry.Lock()
-	defer backendRegistry.Unlock()
-	backendRegistry.backends[name] = backend
-	if backendRegistry.current == "" {
-		backendRegistry.current = name
-	}
-	return nil
-}
-
-func mustRegisterBackend(backend Backend) {
-	if err := RegisterBackend(backend); err != nil {
-		panic(err)
-	}
-}
-
-// UseBackend switches the active git backend implementation.
-func UseBackend(name string) error {
-	backendRegistry.Lock()
-	defer backendRegistry.Unlock()
-	if _, ok := backendRegistry.backends[name]; !ok {
-		return fmt.Errorf("git backend %q is not registered", name)
-	}
-	backendRegistry.current = name
-	return nil
-}
-
-func mustUseBackend(name string) {
-	if err := UseBackend(name); err != nil {
-		panic(err)
-	}
-}
-
-// CurrentBackendName returns the active backend name.
-func CurrentBackendName() string {
-	backendRegistry.RLock()
-	defer backendRegistry.RUnlock()
-	return backendRegistry.current
-}
-
-// RegisteredBackends returns all registered backend names.
-func RegisteredBackends() []string {
-	backendRegistry.RLock()
-	defer backendRegistry.RUnlock()
-	out := make([]string, 0, len(backendRegistry.backends))
-	for name := range backendRegistry.backends {
-		out = append(out, name)
-	}
-	sort.Strings(out)
-	return out
-}
-
-func currentBackend() Backend {
-	backendRegistry.RLock()
-	defer backendRegistry.RUnlock()
-	return backendRegistry.backends[backendRegistry.current]
-}
-
-func setBackendForTesting(t testingT, backend Backend) {
-	t.Helper()
-	prev := CurrentBackendName()
-	mustRegisterBackend(backend)
-	mustUseBackend(backend.Name())
-	t.Cleanup(func() { mustUseBackend(prev) })
-}
-
-type testingT interface {
-	Cleanup(func())
-	Helper()
-}