chore(lint): add golangci-lint v2 and fix all lint issues (#803)

## Summary
- Replace old `.golangci.yml` (v1 format) with v2 format, aligned with gitea's lint config
- Add `lint-go`, `lint-go-fix`, and `lint` Makefile targets using golangci-lint v2.10.1
- Replace `make vet` with `make lint` in CI workflow (lint includes vet)
- Fix all 35 lint issues: modernize (maps.Copy, range over int, any), perfsprint (errors.New), unparam (remove unused parameters), revive (var naming), staticcheck, forbidigo exclusion for cmd/
- Make `security-check` non-fatal (apply https://github.com/go-gitea/gitea/pull/36681)
- Remove dead gocritic exclusion rules (commentFormatting, exitAfterDefer)
- Remove dead linter exclusions and disabled checks (singleCaseSwitch, ST1003, QF1001, QF1006, QF1008, testifylint go-require/require-error, test file exclusions for dupl/errcheck/staticcheck/unparam)

## Test plan
- [x] `golangci-lint run` passes
- [x] `go build ./...` passes
- [x] `go test ./...` passes

---------

Co-authored-by: ChristopherHX <christopher.homberger@web.de>
Co-authored-by: Christopher Homberger <christopher.homberger@web.de>
Reviewed-on: https://gitea.com/gitea/act_runner/pulls/803
Reviewed-by: ChristopherHX <christopherhx@noreply.gitea.com>

.golangci.yml

@@ -1,165 +1,112 @@
+version: "2"
+output:
+  sort-order:
+    - file
 linters:
+  default: none
   enable:
-    - gosimple
-    - typecheck
-    - govet
-    - errcheck
-    - staticcheck
-    - unused
-    - dupl
-    #- gocyclo # The cyclomatic complexety of a lot of functions is too high, we should refactor those another time.
-    - gofmt
-    - misspell
-    - gocritic
     - bidichk
-    - ineffassign
-    - revive
-    - gofumpt
+    - bodyclose
     - depguard
+    - dupl
+    - errcheck
+    - forbidigo
+    - gocheckcompilerdirectives
+    - gocritic
+    - govet
+    - ineffassign
+    - mirror
+    - modernize
     - nakedret
-    - unconvert
-    - wastedassign
+    - nilnil
     - nolintlint
-    - stylecheck
-  enable-all: false
-  disable-all: true
-  fast: false
-
-run:
-  go: 1.18
-  timeout: 10m
-  skip-dirs:
-    - node_modules
-    - public
-    - web_src
-
-linters-settings:
-  stylecheck:
-    checks: ["all", "-ST1005", "-ST1003"]
-  nakedret:
-    max-func-lines: 0
-  gocritic:
-    disabled-checks:
-      - ifElseChain
-      - singleCaseSwitch # Every time this occurred in the code, there  was no other way.
-  revive:
-    ignore-generated-header: false
-    severity: warning
-    confidence: 0.8
-    errorCode: 1
-    warningCode: 1
+    - perfsprint
+    - revive
+    - staticcheck
+    - testifylint
+    - unconvert
+    - unparam
+    - unused
+    - usestdlibvars
+    - usetesting
+    - wastedassign
+  settings:
+    depguard:
+      rules:
+        main:
+          deny:
+            - pkg: io/ioutil
+              desc: use os or io instead
+            - pkg: golang.org/x/exp
+              desc: it's experimental and unreliable
+            - pkg: github.com/pkg/errors
+              desc: use builtin errors package instead
+    nolintlint:
+      allow-unused: false
+      require-explanation: true
+      require-specific: true
+    gocritic:
+      enabled-checks:
+        - equalFold
+      disabled-checks:
+        - ifElseChain
+    revive:
+      severity: error
+      rules:
+        - name: blank-imports
+        - name: constant-logical-expr
+        - name: context-as-argument
+        - name: context-keys-type
+        - name: dot-imports
+        - name: empty-lines
+        - name: error-return
+        - name: error-strings
+        - name: exported
+        - name: identical-branches
+        - name: if-return
+        - name: increment-decrement
+        - name: modifies-value-receiver
+        - name: package-comments
+        - name: redefines-builtin-id
+        - name: superfluous-else
+        - name: time-naming
+        - name: unexported-return
+        - name: var-declaration
+        - name: var-naming
+    staticcheck:
+      checks:
+        - all
+        - -ST1005
+    usetesting:
+      os-temp-dir: true
+    perfsprint:
+      concat-loop: false
+    govet:
+      enable:
+        - nilness
+        - unusedwrite
+  exclusions:
+    generated: lax
+    presets:
+      - comments
+      - common-false-positives
+      - legacy
+      - std-error-handling
     rules:
-      - name: blank-imports
-      - name: context-as-argument
-      - name: context-keys-type
-      - name: dot-imports
-      - name: error-return
-      - name: error-strings
-      - name: error-naming
-      - name: exported
-      - name: if-return
-      - name: increment-decrement
-      - name: var-naming
-      - name: var-declaration
-      - name: package-comments
-      - name: range
-      - name: receiver-naming
-      - name: time-naming
-      - name: unexported-return
-      - name: indent-error-flow
-      - name: errorf
-      - name: duplicated-imports
-      - name: modifies-value-receiver
-  gofumpt:
-    extra-rules: true
-    lang-version: "1.18"
-  depguard:
-    # TODO: use depguard to replace import checks in gitea-vet
-    list-type: denylist
-    # Check the list against standard lib.
-    include-go-root: true
-    packages-with-error-message:
-      - github.com/unknwon/com: "use gitea's util and replacements"
-
+      - linters:
+          - forbidigo
+        path: cmd
 issues:
-  exclude-rules:
-    # Exclude some linters from running on tests files.
-    - path: _test\.go
-      linters:
-        - gocyclo
-        - errcheck
-        - dupl
-        - gosec
-        - unparam
-        - staticcheck
-    - path: models/migrations/v
-      linters:
-        - gocyclo
-        - errcheck
-        - dupl
-        - gosec
-    - linters:
-        - dupl
-      text: "webhook"
-    - linters:
-        - gocritic
-      text: "`ID' should not be capitalized"
-    - path: modules/templates/helper.go
-      linters:
-        - gocritic
-    - linters:
-        - unused
-      text: "swagger"
-    - path: contrib/pr/checkout.go
-      linters:
-        - errcheck
-    - path: models/issue.go
-      linters:
-        - errcheck
-    - path: models/migrations/
-      linters:
-        - errcheck
-    - path: modules/log/
-      linters:
-        - errcheck
-    - path: routers/api/v1/repo/issue_subscription.go
-      linters:
-        - dupl
-    - path: routers/repo/view.go
-      linters:
-        - dupl
-    - path: models/migrations/
-      linters:
-        - unused
-    - linters:
-        - staticcheck
-      text: "argument x is overwritten before first use"
-    - path: modules/httplib/httplib.go
-      linters:
-        - staticcheck
-    # Enabling this would require refactoring the methods and how they are called.
-    - path: models/issue_comment_list.go
-      linters:
-        - dupl
-    - linters:
-        - misspell
-      text: '`Unknwon` is a misspelling of `Unknown`'
-    - path: models/update.go
-      linters:
-        - unused
-    - path: cmd/dump.go
-      linters:
-        - dupl
-    - text: "commentFormatting: put a space between `//` and comment text"
-      linters:
-        - gocritic
-    - text: "exitAfterDefer:"
-      linters:
-        - gocritic
-    - path: modules/graceful/manager_windows.go
-      linters:
-        - staticcheck
-      text: "svc.IsAnInteractiveSession is deprecated: Use IsWindowsService instead."
-    - path: models/user/openid.go
-      linters:
-        - golint
+  max-issues-per-linter: 0
+  max-same-issues: 0
+formatters:
+  enable:
+    - gofmt
+    - gofumpt
+  settings:
+    gofumpt:
+      extra-rules: true
+  exclusions:
+    generated: lax
+run:
+  timeout: 10m