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/kurin/blazer/internal/blog/blog.go

@@ -0,0 +1,54 @@
+// Copyright 2017, the Blazer authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package blog implements a private logger, in the manner of glog, without
+// polluting the flag namespace or leaving files all over /tmp.
+//
+// It has almost no features, and a bunch of global state.
+package blog
+
+import (
+	"log"
+	"os"
+	"strconv"
+)
+
+var level int32
+
+type Verbose bool
+
+func init() {
+	lvl := os.Getenv("B2_LOG_LEVEL")
+	i, err := strconv.ParseInt(lvl, 10, 32)
+	if err != nil {
+		return
+	}
+	level = int32(i)
+}
+
+func (v Verbose) Info(a ...interface{}) {
+	if v {
+		log.Print(a...)
+	}
+}
+
+func (v Verbose) Infof(format string, a ...interface{}) {
+	if v {
+		log.Printf(format, a...)
+	}
+}
+
+func V(target int32) Verbose {
+	return Verbose(target <= level)
+}