ci: remove --no-config; respect project .golangci.yaml (mc#1099)

Root cause of the 5m1s golangci-lint failure (run 48604):
--no-config makes v2.x use ALL default linters including errcheck,
which the project's .golangci.yaml explicitly disables. 30+ errcheck
violations were reported (unchecked fmt.Fprintf, os.Setenv,
rows.Close, etc.) — all legitimately exempted by the project config.

Fix: drop --no-config so the project's config is respected. The
workspace-server/.golangci.yaml has timeout: 3m; override it with
--timeout 30m for cold runner headroom. Cold runner pipeline:
  fetch-depth:0 clone     ~5-10m
  Go toolchain            ~5-10m
  go mod download         ~2-5m
  go build + go vet       ~2-5m
  golangci-lint install   ~2-5m  (cached on warm runner)
  golangci-lint run       ~2-5m  (errcheck disabled → 0 issues)
  = up to 30m total

retry-trigger: 2026-05-15T12:20 UTC (attempt 10 — remove --no-config)

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

.gitea/workflows/ci.yml

@@ -176,12 +176,16 @@ jobs:
         run: go install github.com/golangci/golangci-lint/v2/cmd/golangci-lint@v2.12.2
       - if: success()
         name: Run golangci-lint
-        # mc#1099: --no-config bypasses .golangci.yaml ceiling; --timeout 30m
-        # is the active constraint. Cold runner: fetch-depth:0 clone (5-10m) + Go
-        # toolchain (5-10m) + mod download (2-5m) + build + vet + install lint
-        # (5m) = ~15-20m before linting even starts. 30m gives headroom.
-        # retry-trigger: 2026-05-15T12:05 UTC (attempt 9 — confirm 30m in file)
-        run: $(go env GOPATH)/bin/golangci-lint run --no-config --timeout 30m ./...
+        # mc#1099: remove --no-config. The workspace-server/.golangci.yaml
+        # explicitly disables errcheck; with --no-config, v2.x enables all
+        # default linters (including errcheck) and reports 30+ violations.
+        # Respecting the project config lets the existing errcheck exemptions
+        # keep CI green. Override the 3m config timeout with --timeout 30m
+        # for cold runner headroom: fetch-depth:0 clone + Go toolchain +
+        # mod download + build + vet + install lint (~15-20m) + lint
+        # run (~5-10m) = up to 30m total.
+        # retry-trigger: 2026-05-15T12:20 UTC (attempt 10 — remove --no-config)
+        run: $(go env GOPATH)/bin/golangci-lint run --timeout 30m ./...
       - if: success()
         name: Diagnostic — per-package verbose 600s
         run: |