Merge gitea/act into act/

Merges the `gitea.com/gitea/act` fork into this repository as the `act/`
directory and consumes it as a local package. The `replace github.com/nektos/act
=> gitea.com/gitea/act` directive is removed; act's dependencies are merged
into the root `go.mod`.

- Imports rewritten: `github.com/nektos/act/pkg/...` → `gitea.com/gitea/act_runner/act/...`
  (flattened — `pkg/` boundary dropped to match the layout forgejo-runner adopted).
- Dropped act's CLI (`cmd/`, `main.go`) and all upstream project files; kept
  the library tree + `LICENSE`.
- Added `// Copyright <year> The Gitea Authors ...` / `// Copyright <year> nektos`
  headers to 104 `.go` files.
- Pre-existing act lint violations annotated inline with
  `//nolint:<linter> // pre-existing issue from nektos/act`.
  `.golangci.yml` is unchanged vs `main`.
- Makefile test target: `-race -short` (matches forgejo-runner).
- Pre-existing integration test failures fixed: race in parallel executor
  (atomic counters); TestSetupEnv / command_test / expression_test /
  run_context_test updated to match gitea fork runtime; TestJobExecutor and
  TestActionCache gated on `testing.Short()`.

Full `gitea/act` commit history is reachable via the second parent.

Co-Authored-By: Claude (Opus 4.7) <noreply@anthropic.com>

act/runner/testdata/actions/node20/node_modules/node-fetch/LICENSE.md

@@ -0,0 +1,22 @@
+The MIT License (MIT)
+
+Copyright (c) 2016 David Frank
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+

act/runner/testdata/actions/node20/node_modules/node-fetch/browser.js

@@ -0,0 +1,25 @@
+"use strict";
+
+// ref: https://github.com/tc39/proposal-global
+var getGlobal = function () {
+	// the only reliable means to get the global object is
+	// `Function('return this')()`
+	// However, this causes CSP violations in Chrome apps.
+	if (typeof self !== 'undefined') { return self; }
+	if (typeof window !== 'undefined') { return window; }
+	if (typeof global !== 'undefined') { return global; }
+	throw new Error('unable to locate global object');
+}
+
+var globalObject = getGlobal();
+
+module.exports = exports = globalObject.fetch;
+
+// Needed for TypeScript and Webpack.
+if (globalObject.fetch) {
+	exports.default = globalObject.fetch.bind(globalObject);
+}
+
+exports.Headers = globalObject.Headers;
+exports.Request = globalObject.Request;
+exports.Response = globalObject.Response;

act/runner/testdata/actions/node20/node_modules/node-fetch/package.json

@@ -0,0 +1,89 @@
+{
+    "name": "node-fetch",
+    "version": "2.6.12",
+    "description": "A light-weight module that brings window.fetch to node.js",
+    "main": "lib/index.js",
+    "browser": "./browser.js",
+    "module": "lib/index.mjs",
+    "files": [
+        "lib/index.js",
+        "lib/index.mjs",
+        "lib/index.es.js",
+        "browser.js"
+    ],
+    "engines": {
+        "node": "4.x || >=6.0.0"
+    },
+    "scripts": {
+        "build": "cross-env BABEL_ENV=rollup rollup -c",
+        "prepare": "npm run build",
+        "test": "cross-env BABEL_ENV=test mocha --require babel-register --throw-deprecation test/test.js",
+        "report": "cross-env BABEL_ENV=coverage nyc --reporter lcov --reporter text mocha -R spec test/test.js",
+        "coverage": "cross-env BABEL_ENV=coverage nyc --reporter json --reporter text mocha -R spec test/test.js && codecov -f coverage/coverage-final.json"
+    },
+    "repository": {
+        "type": "git",
+        "url": "https://github.com/bitinn/node-fetch.git"
+    },
+    "keywords": [
+        "fetch",
+        "http",
+        "promise"
+    ],
+    "author": "David Frank",
+    "license": "MIT",
+    "bugs": {
+        "url": "https://github.com/bitinn/node-fetch/issues"
+    },
+    "homepage": "https://github.com/bitinn/node-fetch",
+    "dependencies": {
+        "whatwg-url": "^5.0.0"
+    },
+    "peerDependencies": {
+        "encoding": "^0.1.0"
+    },
+    "peerDependenciesMeta": {
+        "encoding": {
+            "optional": true
+        }
+    },
+    "devDependencies": {
+        "@ungap/url-search-params": "^0.1.2",
+        "abort-controller": "^1.1.0",
+        "abortcontroller-polyfill": "^1.3.0",
+        "babel-core": "^6.26.3",
+        "babel-plugin-istanbul": "^4.1.6",
+        "babel-plugin-transform-async-generator-functions": "^6.24.1",
+        "babel-polyfill": "^6.26.0",
+        "babel-preset-env": "1.4.0",
+        "babel-register": "^6.16.3",
+        "chai": "^3.5.0",
+        "chai-as-promised": "^7.1.1",
+        "chai-iterator": "^1.1.1",
+        "chai-string": "~1.3.0",
+        "codecov": "3.3.0",
+        "cross-env": "^5.2.0",
+        "form-data": "^2.3.3",
+        "is-builtin-module": "^1.0.0",
+        "mocha": "^5.0.0",
+        "nyc": "11.9.0",
+        "parted": "^0.1.1",
+        "promise": "^8.0.3",
+        "resumer": "0.0.0",
+        "rollup": "^0.63.4",
+        "rollup-plugin-babel": "^3.0.7",
+        "string-to-arraybuffer": "^1.0.2",
+        "teeny-request": "3.7.0"
+    },
+    "release": {
+        "branches": [
+            "+([0-9]).x",
+            "main",
+            "next",
+            {
+                "name": "beta",
+                "prerelease": true
+            }
+        ]
+    }
+}