feat(poster-storage): implement S3/Minio storage adapter and configuration

Co-authored-by: Copilot <copilot@github.com>

crates/adapters/poster-storage/src/config.rs

@@ -0,0 +1,38 @@
+use anyhow::Context;
+use object_store::{aws::AmazonS3Builder, ObjectStore};
+use std::sync::Arc;
+
+pub struct StorageConfig {
+    endpoint: String,
+    access_key_id: String,
+    secret_access_key: String,
+    bucket: String,
+    region: String,
+}
+
+impl StorageConfig {
+    pub fn from_env() -> anyhow::Result<Self> {
+        Ok(Self {
+            endpoint: std::env::var("MINIO_ENDPOINT").context("MINIO_ENDPOINT required")?,
+            access_key_id: std::env::var("MINIO_ACCESS_KEY_ID")
+                .context("MINIO_ACCESS_KEY_ID required")?,
+            secret_access_key: std::env::var("MINIO_SECRET_ACCESS_KEY")
+                .context("MINIO_SECRET_ACCESS_KEY required")?,
+            bucket: std::env::var("MINIO_BUCKET").context("MINIO_BUCKET required")?,
+            region: std::env::var("MINIO_REGION").unwrap_or_else(|_| "minio".to_string()),
+        })
+    }
+
+    pub fn build_store(self) -> anyhow::Result<Arc<dyn ObjectStore>> {
+        let store = AmazonS3Builder::new()
+            .with_endpoint(self.endpoint)
+            .with_access_key_id(self.access_key_id)
+            .with_secret_access_key(self.secret_access_key)
+            .with_bucket_name(self.bucket)
+            .with_region(self.region)
+            .with_allow_http(true)
+            .build()
+            .context("Failed to build S3/Minio store")?;
+        Ok(Arc::new(store))
+    }
+}