revert: tea 1.0 rewrite (#1122–#1126) (#1146)

Reverts #1126, #1125, #1124, #1123 and #1122.

`go.mod` keeps the Go 1.26 line with toolchain `go1.26.9` (instead of the original `go1.26.6`) so the security fix from #1131 isn't lost.

reopens #69
reopens #141
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Reviewed-on: https://gitea.com/gitea/tea/pulls/1146
Reviewed-by: TheFox0x7 <95654+thefox0x7@noreply.gitea.com>

modules/context/context_require.go

@@ -0,0 +1,41 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package context
+
+import (
+	"errors"
+)
+
+// Ensure checks if requirements on the context are set.
+func (ctx *TeaContext) Ensure(req CtxRequirement) error {
+	if req.LocalRepo && ctx.LocalRepo == nil {
+		return errors.New("local repository required: execute from a repo dir, or specify a path with --repo")
+	}
+
+	if req.RemoteRepo && len(ctx.RepoSlug) == 0 {
+		return errors.New("remote repository required: specify id via --repo or execute from a local git repo")
+	}
+
+	if req.Org && len(ctx.Org) == 0 {
+		return errors.New("organization required: specify organization via --org")
+	}
+
+	if req.Global && !ctx.IsGlobal {
+		return errors.New("global scope required: specify --global")
+	}
+
+	return nil
+}
+
+// CtxRequirement specifies context needed for operation
+type CtxRequirement struct {
+	// ensures a local git repo is available & ctx.LocalRepo is set. Implies .RemoteRepo
+	LocalRepo bool
+	// ensures ctx.RepoSlug, .Owner, .Repo are set
+	RemoteRepo bool
+	// ensures ctx.Org is set
+	Org bool
+	// ensures ctx.IsGlobal is true
+	Global bool
+}