docs: standardize all configuration examples to singular 'replica' format (#822)

Co-authored-by: Takayuki Miyahara <voyager.3taka28@gmail.com>
Co-authored-by: Claude <noreply@anthropic.com>

.claude/agents/replica-client-developer.md

@@ -101,10 +101,10 @@ go test -race -v ./[backend]/...
 ## Configuration Pattern
 
 ```yaml
-replicas:
-  - type: [backend]
-    option1: value1
-    option2: value2
+replica:
+  type: [backend]
+  option1: value1
+  option2: value2
 ```
 
 ## References

.claude/commands/add-storage-backend.md

@@ -71,10 +71,10 @@ Create a new storage backend implementation for Litestream with all required com
 5. **Add Documentation**
    Update README.md with configuration example:
    ```yaml
-   replicas:
-     - type: {{backend_name}}
-       option1: value1
-       option2: value2
+   replica:
+     type: {{backend_name}}
+     option1: value1
+     option2: value2
    ```
 
 ## Key Requirements

.github/workflows/commit.yml

@@ -372,13 +372,13 @@ jobs:
           cat > /tmp/sftp-concurrent.yml <<EOF
           dbs:
             - path: /tmp/test-concurrent.db
-              replicas:
-                - type: sftp
-                  host: localhost:2222
-                  key-path: /test/id_ed25519
-                  user: root
-                  path: /test/data/concurrent
-                  concurrent-writes: true
+              replica:
+                type: sftp
+                host: localhost:2222
+                key-path: /test/id_ed25519
+                user: root
+                path: /test/data/concurrent
+                concurrent-writes: true
           EOF
 
           # Create test database
@@ -398,12 +398,12 @@ jobs:
           cat > /tmp/sftp-sequential.yml <<EOF
           dbs:
             - path: /tmp/test-sequential.db
-              replicas:
-                - type: sftp
-                  host: localhost:2222
-                  key-path: /test/id_ed25519
-                  user: root
-                  path: /test/data/sequential
+              replica:
+                type: sftp
+                host: localhost:2222
+                key-path: /test/id_ed25519
+                user: root
+                path: /test/data/sequential
                   concurrent-writes: false
           EOF
 

AGENTS.md

@@ -773,11 +773,11 @@ l0-retention: 5m                 # Minimum time to keep compacted L0 files
 l0-retention-check-interval: 15s # Frequency for enforcing L0 retention
 dbs:
   - path: /path/to/db.sqlite
-    replicas:
-      - type: s3
-        bucket: my-bucket
-        path: db-backup
-        sync-interval: 10s  # How often to sync
+    replica:
+      type: s3
+      bucket: my-bucket
+      path: db-backup
+      sync-interval: 10s  # How often to sync
 
 # Compaction configuration (default)
 levels:

etc/litestream.yml

@@ -4,21 +4,23 @@
 
 # dbs:
 #  - path: /path/to/primary/db            # Database to replicate from
-#    replicas:
-#      - path: /path/to/replica           # File-based replication
-#      - url:  s3://my.bucket.com/db      # S3-based replication
-#      - type: nats                       # NATS JetStream replication
-#        url: nats://nats.example.com:4222
-#        bucket: litestream-backups
-#        # Optional TLS configuration:
-#        # client-cert: /path/to/client.pem
-#        # client-key: /path/to/client.key
-#        # root-cas: [/path/to/ca.pem]
-#      - url: sftp://user@host:22/path    # SFTP-based replication
-#        key-path: /etc/litestream/sftp_key
-#        # Strongly recommended: SSH host key for verification
-#        # Get this from the server's /etc/ssh/ssh_host_*.pub file
-#        # or use `ssh-keyscan hostname`
-#        # Example formats:
-#        # host-key: ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIMvvypUkBrS9RCyV//p+UFCLg8yKNtTu/ew/cV6XXAAP
-#        # host-key: ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQ...
+#    replica:
+#      path: /path/to/replica             # File-based replication
+#      url:  s3://my.bucket.com/db        # S3-based replication
+#      type: nats                         # NATS JetStream replication
+#      url: nats://nats.example.com:4222
+#      bucket: litestream-backups
+#      # Optional TLS configuration:
+#      # client-cert: /path/to/client.pem
+#      # client-key: /path/to/client.key
+#      # root-cas: [/path/to/ca.pem]
+#  - path: /path/to/another/db
+#    replica:
+#      url: sftp://user@host:22/path      # SFTP-based replication
+#      key-path: /etc/litestream/sftp_key
+#      # Strongly recommended: SSH host key for verification
+#      # Get this from the server's /etc/ssh/ssh_host_*.pub file
+#      # or use `ssh-keyscan hostname`
+#      # Example formats:
+#      # host-key: ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIMvvypUkBrS9RCyV//p+UFCLg8yKNtTu/ew/cV6XXAAP
+#      # host-key: ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQ...

tests/integration/soak_helpers.go

@@ -408,8 +408,8 @@ func CreateSoakConfig(dbPath, replicaURL string, s3Config *S3Config, shortMode b
 	config.WriteString("    min-checkpoint-page-count: 100\n")
 	config.WriteString("    max-checkpoint-page-count: 5000\n")
 	config.WriteString("\n")
-	config.WriteString("    replicas:\n")
-	config.WriteString(fmt.Sprintf("      - url: %s\n", replicaURL))
+	config.WriteString("    replica:\n")
+	config.WriteString(fmt.Sprintf("      url: %s\n", replicaURL))
 
 	// Add S3-specific settings if provided
 	if s3Config != nil {