build: update Go to 1.27.1 and modernize the codebase (#2798)

Toolchain and CI:
- Bump go directive from 1.26.8 to 1.27.1 (go.mod)
- Use golang:1.27-alpine builder images in all Dockerfiles
- Bump golangci-lint to v2.13.2 (first release with go1.27 support)
- Add CI gate: `go fix -diff` fails when outdated Go patterns are
  detected (locally: `make check-modernize`)

Note: darwin binaries now require macOS 13 or later.

Lint fixes required by golangci-lint v2.13.2:
- goconst: ignore tests (all 436 findings were test-only; goconst
  got stricter since v2.12 and this option was added for it)
- openai.go: keep deprecated MaxTokens deliberately with a nolint
  rationale (max_tokens is the only form universally supported by
  OpenAI-compatible backends like One-API, LiteLLM, Ollama shim)
- state.go: drop always-nil flags param from appendChartVersionFlags
  (renamed to chartVersionFlags, unparam)

Modernization (go fix ./..., 62 files):
- interface{} -> any, maps.Copy, strings.SplitSeq, range-over-int,
  builtin min/max, slices.Contains/ContainsFunc/Sort, WaitGroup.Go,
  reflect.Type.Fields(), new(expr)
- exit_error.go: strings.Builder + fmt.Fprintf instead of string
  concatenation and WriteString(fmt.Sprintf(...)) (QF1012)
- chart_dependency.go: strings.CutLast for OCI dependency helpers

Signed-off-by: yxxhero <aiopsclub@163.com>
Co-authored-by: Claude <noreply@anthropic.com>

pkg/event/bus.go

@@ -3,6 +3,7 @@ package event
 import (
 	goContext "context"
 	"fmt"
+	"maps"
 	"os"
 	"strconv"
 	"strings"
@@ -149,9 +150,7 @@ func (bus *Bus) runHook(hook Hook, evt string, evtErr error, context map[string]
 			Error: evtErr,
 		},
 	}
-	for k, v := range context {
-		data[k] = v
-	}
+	maps.Copy(data, context)
 	render := tmpl.NewTextRenderer(bus.Fs, bus.BasePath, data)
 
 	bus.Logger.Debugf("hook[%s]: triggered by event \"%s\"\n", name, evt)

pkg/event/bus_test.go

@@ -347,8 +347,7 @@ func TestTriggerCleanupEventWithNilError(t *testing.T) {
 }
 
 func TestBusDefaultRunnerUsesCtxWhenSet(t *testing.T) {
-	ctx, cancel := goContext.WithCancel(goContext.Background())
-	defer cancel()
+	ctx := t.Context()
 
 	bus := &Bus{Ctx: ctx, Logger: zap.NewNop().Sugar()}