fix(container): remove hadolint ignore directives (root cause)

Commit 9f064c5 added `# hadolint ignore=DL3018,SC2261` to suppress
hadolint warnings on apk fuzzy `>=` pins. The new Rule Integrity
(post v0.4.0 retro, CLAUDE.md amendment) bans ALL linter
suppression directives in any language. Fix root cause.

Revert to exact `-rN` pins accepted by both apk and hadolint:
- ca-certificates=20260413-r0
- tzdata=2026a-r0
- wget=1.25.0-r1

Trade-off: Alpine revision rotation (-r0 → -r1) breaks future
builds; bump manually on Alpine updates. Renovate auto-bump
config deferred to v0.5.x. Rotation warning documented above
each apk RUN block.

Step 10b PRE-PUSH VERIFY (new workflow):
- git status: only Dockerfile changed
- hadolint Dockerfile: 0 warnings
- docker build -t pebblify:test .: success
- go vet ./...: clean
- golangci-lint run ./...: 0 issues
- 4-target cross-compile: PASS

Closes #42

Author: nayrosk

Dockerfile

@@ -8,8 +8,12 @@ ARG TARGETARCH
 ARG VERSION=dev
 ARG REVISION=unknown
 
-# hadolint ignore=DL3018,SC2261
-RUN apk add --no-cache ca-certificates>=20260413 tzdata>=2026a
+# Alpine package pins are exact (including -rN revision). Rotation to a new
+# revision will break this build; bump manually on Alpine package updates.
+# Automated bumps deferred to v0.5.x (Renovate config).
+RUN apk add --no-cache \
+        ca-certificates=20260413-r0 \
+        tzdata=2026a-r0
 
 WORKDIR /build
 
@@ -46,11 +50,13 @@ LABEL org.opencontainers.image.title="Pebblify" \
       org.opencontainers.image.created="${CREATED}" \
       org.opencontainers.image.base.name="alpine:3.22"
 
-# hadolint ignore=DL3018,SC2261
+# Alpine package pins are exact (including -rN revision). Rotation to a new
+# revision will break this build; bump manually on Alpine package updates.
+# Automated bumps deferred to v0.5.x (Renovate config).
 RUN apk add --no-cache \
-        ca-certificates>=20260413 \
-        tzdata>=2026a \
-        wget>=1.25.0 \
+        ca-certificates=20260413-r0 \
+        tzdata=2026a-r0 \
+        wget=1.25.0-r1 \
     && addgroup -g 10000 pebblify \
     && adduser -D -H -u 10000 -G pebblify -s /sbin/nologin pebblify