Switch to govips for native CGO image processing

- Replace gen2brain/avif, gen2brain/webp, disintegration/imaging with govips
- govips uses libvips via CGO for fast native image processing
- Add libheif-dev to Dockerfile for AVIF support
- Add docker-test Makefile target for running tests in Docker
- Update processor.go to use vips API for decode, resize, encode
- Add TestMain to initialize/shutdown vips in tests
- Remove WASM-based libraries (gen2brain) in favor of native codecs

Performance improvement: AVIF encoding now uses native libheif instead of
WASM, significantly reducing encoding time for large images.

go.mod

@@ -5,16 +5,18 @@ go 1.25.4
 require (
 	git.eeqj.de/sneak/smartconfig v1.0.0
 	github.com/99designs/basicauth-go v0.0.0-20230316000542-bf6f9cbbf0f8
-	github.com/disintegration/imaging v1.6.2
+	github.com/davidbyttow/govips/v2 v2.16.0
+	github.com/dustin/go-humanize v1.0.1
+	github.com/fxamacker/cbor/v2 v2.9.0
 	github.com/getsentry/sentry-go v0.40.0
 	github.com/go-chi/chi/v5 v5.2.3
 	github.com/go-chi/cors v1.2.2
+	github.com/gorilla/securecookie v1.1.2
 	github.com/prometheus/client_golang v1.23.2
 	github.com/slok/go-http-metrics v0.13.0
 	github.com/spf13/cobra v1.10.2
 	go.uber.org/fx v1.24.0
 	golang.org/x/crypto v0.41.0
-	golang.org/x/image v0.34.0
 	modernc.org/sqlite v1.42.2
 )
 
@@ -51,14 +53,9 @@ require (
 	github.com/coreos/go-semver v0.3.1 // indirect
 	github.com/coreos/go-systemd/v22 v22.5.0 // indirect
 	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
-	github.com/dustin/go-humanize v1.0.1 // indirect
-	github.com/ebitengine/purego v0.8.3 // indirect
 	github.com/emicklei/go-restful/v3 v3.12.1 // indirect
 	github.com/fatih/color v1.16.0 // indirect
 	github.com/felixge/httpsnoop v1.0.4 // indirect
-	github.com/fxamacker/cbor/v2 v2.9.0 // indirect
-	github.com/gen2brain/avif v0.4.4 // indirect
-	github.com/gen2brain/webp v0.5.5 // indirect
 	github.com/go-jose/go-jose/v4 v4.0.5 // indirect
 	github.com/go-logr/logr v1.4.2 // indirect
 	github.com/go-logr/stdr v1.2.2 // indirect
@@ -74,7 +71,6 @@ require (
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/googleapis/enterprise-certificate-proxy v0.3.6 // indirect
 	github.com/googleapis/gax-go/v2 v2.14.2 // indirect
-	github.com/gorilla/securecookie v1.1.2 // indirect
 	github.com/grpc-ecosystem/grpc-gateway/v2 v2.26.3 // indirect
 	github.com/hashicorp/consul/api v1.32.1 // indirect
 	github.com/hashicorp/errwrap v1.1.0 // indirect
@@ -112,7 +108,6 @@ require (
 	github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
 	github.com/ryanuber/go-glob v1.0.0 // indirect
 	github.com/spf13/pflag v1.0.10 // indirect
-	github.com/tetratelabs/wazero v1.9.0 // indirect
 	github.com/tidwall/gjson v1.18.0 // indirect
 	github.com/tidwall/match v1.1.1 // indirect
 	github.com/tidwall/pretty v1.2.0 // indirect
@@ -131,6 +126,7 @@ require (
 	go.uber.org/zap v1.27.0 // indirect
 	go.yaml.in/yaml/v2 v2.4.2 // indirect
 	golang.org/x/exp v0.0.0-20250620022241-b7579e27df2b // indirect
+	golang.org/x/image v0.34.0 // indirect
 	golang.org/x/net v0.43.0 // indirect
 	golang.org/x/oauth2 v0.30.0 // indirect
 	golang.org/x/sync v0.19.0 // indirect