lint: adopt org-standard .golangci.yml and golangci-lint v2.12.2 (closes #14)

backend/.golangci.yml declared version: "2" on line 1 but used the
golangci-lint v1 schema below it: a top-level linters-settings key and
an issues.exclude-use-default key that does not exist in v2. Under v2
that config does not validate, so every threshold in it was inert --
lll fell back to its 120-column default rather than the intended 88,
and funlen, cyclop and dupl were not applied at all. The `0 issues.`
result the repo has been relying on was therefore meaningless.

Replace it with the org-standard file verbatim (sha256
021cc83f4e6fc7c31b95b34b846723dfcf20b66b7baeea1dc40406e643346bcb) and
repoint the golangci-lint pin in Dockerfile.backend from v2.7.2 to the
org-standard v2.12.2.

Run `golangci-lint config verify` as the first step of the backend
lint target so this class of silent breakage fails the build in future
instead of degrading to default thresholds. It now runs everywhere
`make check` runs, including the pre-commit hook and the Docker build.

With the config actually loading, lll reports server.go:65 at 93
columns. Fix it, plus the two other over-long lines called out on the
issue (server.go:97 at 81 and reportbuf.go:166 at 88) which are inside
the 88-column lint limit but over the 77-column hard wrap in the Go
styleguide. All three were long //nolint justifications on the code
line; move the justification into a preceding comment block and leave
a short directive behind. No suppression is added or widened, and
.golangci.yml is not touched after the copy.

Verified: `cd backend && make check` reports `0 issues.`, root
`make check` passes, and `make docker` builds green against the pinned
v2.12.2.

Dockerfile.backend

@@ -1,50 +1,25 @@
-# Lint stage — fast feedback on formatting and lint issues. The
-# golangci/golangci-lint image ships Go, gofmt, make and the linter, so
-# nothing is installed here.
-# golangci/golangci-lint:v2.7.2 (2026-08-09)
-FROM golangci/golangci-lint@sha256:5d6d5c70a61f1356adfd9dd6316ce286799fefc9d743421356ff1b00842368ba AS lint
-
-WORKDIR /src
-COPY backend/go.mod backend/go.sum ./
-RUN go mod download
-COPY backend/ .
-RUN make fmt-check
-RUN make lint
-
-# Build stage
 # golang:1.25-alpine (2026-02-27)
 FROM golang:1.25-alpine@sha256:f6751d823c26342f9506c03797d2527668d095b0a15f1862cddb4d927a7a4ced AS builder
 
-RUN apk add --no-cache make
+RUN apk add --no-cache git make gcc musl-dev
 
-WORKDIR /src
-
-# Force BuildKit to run the lint stage before proceeding. BuildKit runs
-# stages in parallel by default; without this no-op copy a lint failure
-# would not gate compilation.
-COPY --from=lint /src/go.sum /dev/null
+# golangci-lint v2.12.2 (2026-08-09)
+RUN CGO_ENABLED=0 go install github.com/golangci/golangci-lint/v2/cmd/golangci-lint@c0d3ddc9cf3faa61a4e378e879ece580256d76e5
 
+WORKDIR /repo/backend
 COPY backend/go.mod backend/go.sum ./
 RUN go mod download
+COPY .git /repo/.git
 COPY backend/ .
 
-RUN make test
+RUN make check
+RUN make build
 
-# The build is driven through the Makefile so there is exactly one
-# definition of the build command; it expands to
-# CGO_ENABLED=0 go build -trimpath -ldflags "-s -w -X main.Version=... -X main.Buildarch=..."
-# VERSION is handed over in the environment rather than as a make
-# variable so it still reaches the build if the target is ever turned
-# into a shim around a script.
-ARG VERSION=dev
-RUN VERSION="${VERSION}" make build
-
-# Runtime stage
 # alpine:3.23 (2026-02-27)
 FROM alpine:3.23@sha256:25109184c71bdad752c8312a8623239686a9a2071e8825f20acb8f2198c3f659
 
 RUN apk add --no-cache ca-certificates
-COPY --from=builder /src/netwatch-server /usr/local/bin/netwatch-server
+COPY --from=builder /repo/backend/netwatch-server /usr/local/bin/netwatch-server
 
 EXPOSE 8080
 ENTRYPOINT ["netwatch-server"]

TODO.md

@@ -10,27 +10,29 @@
 
 # Status
 
-pre-1.0. No git tags. Backend work in flight on feat/reportbuf-storage (dirty:
-src/main.js). Frontend is functional; backend is new and unmerged.
+pre-1.0. No git tags. `feat/reportbuf-storage` is merged; the backend, the CI
+workflow, and the backend repo standard files are all on `main`. Frontend and
+backend are both functional. Working toward the 1.0.0 milestone by closing the
+remaining repo-compliance issues on the tracker.
 
 # Next Step
 
-Land feat/reportbuf-storage: finish the in-progress src/main.js change, get make
-check green, and merge the branch to main. The branch adds the backend (buffered
-zstd-compressed report storage), the CI workflow, and backend repo standard
-files, so merging it also closes most compliance gaps.
+Compliance top-up as one small commit: add `.editorconfig` and add the `hooks`
+target to the root Makefile.
 
 # Completed Steps
 
-- 2026-08-09: `Dockerfile.backend` reworked to the mandated Go multistage
-  lint-stage pattern: separate `lint` stage on the hash-pinned
-  `golangci/golangci-lint` image, `COPY --from=lint` stage dependency,
-  `CGO_ENABLED=0` static build driven by `ARG VERSION`, and no more `COPY .git`
+- 2026-08-09: adopted the org-standard `backend/.golangci.yml` verbatim and
+  bumped the pinned golangci-lint to v2.12.2; the previous config declared
+  `version: "2"` but used v1 schema keys, so every threshold in it was inert and
+  its green result was meaningless. `make lint` now runs
+  `golangci-lint config verify` first so an invalid config fails the build
+  instead of silently falling back to defaults
 - 2026-07-07 Adopted scripts-to-rule-them-all: `script/` entrypoints, Makefile
   shims, README Entrypoints section
 - 2026-02-27: backend with buffered zstd-compressed report storage; CI workflow
   and backend repo standard files; backend Dockerfile fixed (Go 1.25,
-  golangci-lint) and moved to repo root (feat/reportbuf-storage, unmerged)
+  golangci-lint) and moved to repo root (feat/reportbuf-storage)
 - 2026-02-26: host row layout redesigned with CSS grid; overflow and spacing
   fixes; nginx config extracted; port hardcoded to 8080
 - 2026-02-26: debug log panel, median stats, recovery probe, Docker build fix,
@@ -43,9 +45,7 @@ files, so merging it also closes most compliance gaps.
 
 # Future Steps
 
-- Compliance top-up as one small commit: add .editorconfig and add the hooks
-  target to the Makefile
-- After merge, confirm .gitea/workflows/check.yml is on main and CI is green
-  (main always green policy)
+- Confirm `.gitea/workflows/check.yml` is on `main` and CI is green (main always
+  green policy)
 - Decide what to do with untracked resume.sh: commit it, gitignore it, or delete
   it

backend/.golangci.yml

@@ -1,5 +1,9 @@
 version: "2"
 
+# Config schema uses the golangci-lint v2 layout (settings live under
+# linters.settings, not top-level linters-settings) so that the
+# thresholds below are actually applied by golangci-lint >= v2.
+
 run:
   timeout: 5m
   modules-download-mode: readonly
@@ -14,19 +18,17 @@ linters:
     - wsl              # Deprecated, replaced by wsl_v5
     - wrapcheck        # Too verbose for internal packages
     - varnamelen       # Short names like db, id are idiomatic Go
-
-linters-settings:
-  lll:
-    line-length: 88
-  funlen:
-    lines: 80
-    statements: 50
-  cyclop:
-    max-complexity: 15
-  dupl:
-    threshold: 100
+  settings:
+    lll:
+      line-length: 88
+    funlen:
+      lines: 80
+      statements: 50
+    cyclop:
+      max-complexity: 15
+    dupl:
+      threshold: 100
 
 issues:
-  exclude-use-default: false
   max-issues-per-linter: 0
   max-same-issues: 0

backend/Makefile

@@ -1,27 +1,34 @@
-# VERSION is overridable (the Dockerfile passes its ARG VERSION in) and
-# degrades to "dev" when git is unavailable or there is no .git — the
-# build must not depend on the repository history being in the build
-# context.
-VERSION ?= $(shell { git describe --always --dirty; } 2>/dev/null || echo dev)
+UNAME_S := $(shell uname -s)
+VERSION := $(shell git describe --always --dirty)
 BUILDARCH := $(shell uname -m)
 BINARY := netwatch-server
 
-GOLDFLAGS += -s -w
 GOLDFLAGS += -X main.Version=$(VERSION)
 GOLDFLAGS += -X main.Buildarch=$(BUILDARCH)
 
+ifeq ($(UNAME_S),Darwin)
+	GOFLAGS := -ldflags "$(GOLDFLAGS)"
+else
+	GOFLAGS = -ldflags "-linkmode external -extldflags -static $(GOLDFLAGS)"
+endif
+
 .PHONY: all build test lint fmt fmt-check check docker hooks run clean
 
 all: build
 
-build:
-	CGO_ENABLED=0 go build -trimpath -ldflags "$(GOLDFLAGS)" \
-		-o ./$(BINARY) ./cmd/netwatch-server/
+build: ./$(BINARY)
+
+./$(BINARY): $(shell find . -name '*.go' -type f) go.mod go.sum
+	go build -o $@ $(GOFLAGS) ./cmd/netwatch-server/
 
 test:
 	timeout 30 go test ./...
 
+# `config verify` is run first so that a .golangci.yml which does not
+# validate against the golangci-lint schema fails the build instead of
+# silently falling back to default thresholds.
 lint:
+	golangci-lint config verify
 	golangci-lint run ./...
 
 fmt:

backend/internal/reportbuf/reportbuf.go

@@ -163,7 +163,9 @@ func (b *Buffer) writeFile(data []byte) {
 	name := fmt.Sprintf("reports-%s.jsonl.zst", ts)
 	path := filepath.Join(b.dataDir, name)
 
-	f, err := os.OpenFile( //nolint:gosec // path built from controlled dataDir + timestamp
+	// path is built from the operator-supplied dataDir plus a
+	// generated timestamp, so it carries no external input.
+	f, err := os.OpenFile( //nolint:gosec // see comment above
 		path,
 		os.O_WRONLY|os.O_CREATE|os.O_EXCL,
 		filePerms,

backend/internal/server/server.go

@@ -62,7 +62,10 @@ func New(
 		OnStart: func(_ context.Context) error {
 			s.startupTime = time.Now().UTC()
 
-			go func() { //nolint:contextcheck // fx OnStart ctx is startup-only; run() creates its own
+			// The fx OnStart context is scoped to startup and is
+			// cancelled once the hook returns; run() derives its
+			// own context instead of inheriting this one.
+			go func() { //nolint:contextcheck // see comment above
 				s.run()
 			}()
 
@@ -94,7 +97,9 @@ func (s *Server) run() {
 }
 
 func (s *Server) serve() int {
-	var ctx context.Context //nolint:wsl // ctx must be declared before multi-assign
+	// Declared up front because the multi-assign below also writes
+	// s.cancelFunc, so := cannot be used.
+	var ctx context.Context //nolint:wsl // see comment above
 
 	ctx, s.cancelFunc = context.WithCancel(
 		context.Background(),