feat(web): improve UI responsiveness, polish, and update docs

- Add mobile/tablet responsive breakpoints to web UI
- Redesign cards as full-bleed poster layout with gradient overlay
- Add skeleton loading state, comic count badge, and search icon
- Switch to Docker image format for registry compatibility
- Add docker-build and docker-push Makefile targets with versioned tags
- Update README to document web UI, Docker deployment, and serve command

Makefile

@@ -1,7 +1,9 @@
 BIN := yoink
 BUILD_DIR := build
+REGISTRY := git.brizzle.dev/bryan/yoink-go
+VERSION := $(shell git describe --tags --always --dirty)
 
-.PHONY: all windows linux darwin clean
+.PHONY: all windows linux darwin clean docker-build docker-push
 
 all: windows linux darwin
 
@@ -16,5 +18,15 @@ darwin:
 	GOOS=darwin GOARCH=amd64 go build -o $(BUILD_DIR)/$(BIN)-darwin-amd64
 	GOOS=darwin GOARCH=arm64 go build -o $(BUILD_DIR)/$(BIN)-darwin-arm64
 
+docker-build:
+	podman build --format docker \
+		-t $(REGISTRY):$(VERSION) \
+		-t $(REGISTRY):latest \
+		.
+
+docker-push: docker-build
+	podman push $(REGISTRY):$(VERSION)
+	podman push $(REGISTRY):latest
+
 clean:
 	rm -rf $(BUILD_DIR)