docs: add OCI storage volume expansion guide

docs/infrastructure-base.md

@@ -4,6 +4,7 @@
 * **Provider**: Oracle Cloud Infrastructure (OCI)
 * **Architecture**: Ampere A1 Flex (`aarch64` / ARM64)
 * **Resources**: 4 OCPUs (Neoverse N1), 24 GB System RAM
+* **Storage Allocation**: 200 GB Always Free Block Volume (Resized Boot Volume)
 * **Memory Strategy**:
   * Container JVM Heap (`-Xmx12G -Xms12G`): Allocated per instance manifest
   * Host OS & Page Cache: Minimum 12 GB reserved for kernel, filesystem page cache, and Docker daemon overhead
@@ -46,3 +47,33 @@ Ensure host user retains ownership of container data to prevent `PermissionError
 sudo chown -R $USER:$USER ./data
 chmod -R u+rwX ./data
 ```
+
+---
+
+## 4. OCI Storage Volume Expansion (Always Free Tier)
+
+Oracle Cloud allows up to 200 GB of Always Free block volume storage per tenancy. To expand the default 47 GB boot volume on Ubuntu instances without reinstalling:
+
+### Phase 1: OCI Console Allocation
+1. In OCI Console, navigate to **Compute** $\rightarrow$ **Instances** $\rightarrow$ `[Your Instance]` $\rightarrow$ **Storage** / **Boot Volume**.
+2. Select **View boot volume details** $\rightarrow$ **Edit**.
+3. Change volume size from `47 GB` up to `200 GB` and save.
+
+### Phase 2: Live Kernel Rescan & Partition Growth (Ubuntu)
+Execute on the host terminal to rescan the block device and resize the online `ext4` filesystem:
+
+```bash
+# 1. Force kernel rescan of resized OCI paravirtualized disk
+sudo dd iflag=direct if=/dev/oracleoci/oraclevda of=/dev/null count=1
+echo "1" | sudo tee /sys/class/block/`readlink /dev/oracleoci/oraclevda | cut -d'/' -f 2`/device/rescan
+
+# 2. Grow partition 1 on /dev/sda
+sudo apt-get update && sudo apt-get install -y cloud-guest-utils
+sudo growpart /dev/sda 1
+
+# 3. Resize ext4 filesystem online
+sudo resize2fs /dev/sda1
+
+# 4. Verify capacity (Target: ~190G+ available)
+df -h /
+```