deps: update vendor dependencies for S3-compatible storage

Updates AWS SDK and removes Blazer B2 dependency in favor of unified
S3-compatible approach. Includes configuration examples and documentation.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

vendor/github.com/aws/aws-sdk-go/private/protocol/restjson/restjson.go

@@ -0,0 +1,59 @@
+// Package restjson provides RESTful JSON serialization of AWS
+// requests and responses.
+package restjson
+
+//go:generate go run -tags codegen ../../../private/model/cli/gen-protocol-tests ../../../models/protocol_tests/input/rest-json.json build_test.go
+//go:generate go run -tags codegen ../../../private/model/cli/gen-protocol-tests ../../../models/protocol_tests/output/rest-json.json unmarshal_test.go
+
+import (
+	"github.com/aws/aws-sdk-go/aws/request"
+	"github.com/aws/aws-sdk-go/private/protocol/jsonrpc"
+	"github.com/aws/aws-sdk-go/private/protocol/rest"
+)
+
+// BuildHandler is a named request handler for building restjson protocol
+// requests
+var BuildHandler = request.NamedHandler{
+	Name: "awssdk.restjson.Build",
+	Fn:   Build,
+}
+
+// UnmarshalHandler is a named request handler for unmarshaling restjson
+// protocol requests
+var UnmarshalHandler = request.NamedHandler{
+	Name: "awssdk.restjson.Unmarshal",
+	Fn:   Unmarshal,
+}
+
+// UnmarshalMetaHandler is a named request handler for unmarshaling restjson
+// protocol request metadata
+var UnmarshalMetaHandler = request.NamedHandler{
+	Name: "awssdk.restjson.UnmarshalMeta",
+	Fn:   UnmarshalMeta,
+}
+
+// Build builds a request for the REST JSON protocol.
+func Build(r *request.Request) {
+	rest.Build(r)
+
+	if t := rest.PayloadType(r.Params); t == "structure" || t == "" {
+		if v := r.HTTPRequest.Header.Get("Content-Type"); len(v) == 0 {
+			r.HTTPRequest.Header.Set("Content-Type", "application/json")
+		}
+		jsonrpc.Build(r)
+	}
+}
+
+// Unmarshal unmarshals a response body for the REST JSON protocol.
+func Unmarshal(r *request.Request) {
+	if t := rest.PayloadType(r.Data); t == "structure" || t == "" {
+		jsonrpc.Unmarshal(r)
+	} else {
+		rest.Unmarshal(r)
+	}
+}
+
+// UnmarshalMeta unmarshals response headers for the REST JSON protocol.
+func UnmarshalMeta(r *request.Request) {
+	rest.UnmarshalMeta(r)
+}