Bumps golangci-lint from v2.11.3 to v2.12.2 and adopts the canonical lint config.
## Version pins
- `Dockerfile`: `golangci/golangci-lint:v2.12.2` Debian image, pinned by digest, dated `2026-08-07`
- `script/bootstrap`: `GOLANGCI_LINT_VERSION=2.12.2` with updated sha256 pins for the `linux-amd64` and `linux-arm64` release archives
## Config
`.golangci.yml` replaced with the canonical config. The previous file kept `lll`/`funlen`/`cyclop`/`dupl` settings under the top-level `linters-settings` key, which the v2 schema ignores; the canonical config nests them under `linters.settings`, so those thresholds now actually apply. The unsupported `issues.exclude-use-default` key was dropped.
## Lint fixes (32 findings)
- `lll` (7): wrapped or shortened over-length lines (struct tag comments moved above fields, test logger construction split, `session.NewForTest` signature wrapped, shortened a `#nosec` comment)
- `goconst` (17): replaced repeated `"POST"`/`"PUT"` literals with `http.MethodPost`/`http.MethodPut`, added shared test constants for `webhooker-test`/`test`/`application/json`, and added `tmplKeyError`/`tmplKeyWebhook` constants for template data keys in `internal/handlers`
- `dupl` (8): merged `buildHTTPTargetConfig` and `buildSlackTargetConfig` into a parameterized `buildURLTargetConfig`; removed the duplicate `iWebhookDB` test helper in favor of `testWebhookDB`; extracted shared helpers in middleware and session tests
No `//nolint` directives were added and behavior is unchanged. `make check` (fmt-check, tests, lint) passes.
Note: golangci-lint v2.12 deprecates the `gomodguard` linter in favor of `gomodguard_v2`; the canonical config change for that is left for a future coordinated update.
Co-authored-by: sneak <sneak@sneak.berlin>
Reviewed-on: #86
Co-authored-by: clawbot <clawbot@noreply.example.org>
Co-committed-by: clawbot <clawbot@noreply.example.org>
Closes [issue #50](#50)
## Summary
Refactors the Dockerfile to use a separate lint stage with a pinned golangci-lint Docker image, following the pattern used by [sneak/pixa](https://git.eeqj.de/sneak/pixa). This replaces the previous approach of installing golangci-lint via curl in the builder stage.
## Changes
### Dockerfile
- **New `lint` stage** using `golangci/golangci-lint:v2.11.3` (Debian-based, pinned by sha256 digest) as a separate build stage
- **Builder stage** depends on lint via `COPY --from=lint /src/go.sum /dev/null` — build won't proceed unless linting passes
- **Go bumped** from 1.24 to 1.26.1 (`golang:1.26.1-bookworm`, pinned by sha256)
- **golangci-lint bumped** from v1.64.8 to v2.11.3
- All three Docker images (golangci-lint, golang, alpine) pinned by sha256 digest
- Debian-based golangci-lint image used (not Alpine) because mattn/go-sqlite3 CGO does not compile on musl (off64_t)
### Linter Config (.golangci.yml)
- Migrated from v1 to v2 format (`version: "2"` added)
- Removed linters no longer available in v2: `gofmt` (handled by `make fmt-check`), `gosimple` (merged into `staticcheck`), `typecheck` (always-on in v2)
- Same set of linters enabled — no rules weakened
### Code Fixes (all lint issues from v2 upgrade)
- Added package comments to all packages
- Added doc comments to all exported types, functions, and methods
- Fixed unchecked errors flagged by `errcheck` (sqlDB.Close, os.Setenv in tests, resp.Body.Close, fmt.Fprint)
- Fixed unused parameters flagged by `revive` (renamed to `_`)
- Fixed `gosec` G120 warnings: added `http.MaxBytesReader` before `r.ParseForm()` calls
- Fixed `staticcheck` QF1012: replaced `WriteString(fmt.Sprintf(...))` with `fmt.Fprintf`
- Fixed `staticcheck` QF1003: converted if/else chain to tagged switch
- Renamed `DeliveryTask` → `Task` to avoid package stutter (`delivery.Task` instead of `delivery.DeliveryTask`)
- Renamed shadowed builtin `max` parameter to `upperBound` in `cryptoRandInt`
- Used `t.Setenv` instead of `os.Setenv` in tests (auto-restores)
### README.md
- Updated version requirements: Go 1.26+, golangci-lint v2.11+
- Updated Dockerfile description in project structure
## Verification
`docker build .` passes cleanly — formatting check, linting, all tests, and build all succeed.
Co-authored-by: clawbot <clawbot@noreply.git.eeqj.de>
Reviewed-on: #55
Co-authored-by: clawbot <clawbot@noreply.example.org>
Co-committed-by: clawbot <clawbot@noreply.example.org>
