update: Revise README and add API reference and configuration schema documentation

docs/CONFIG_SCHEMA.md

@@ -0,0 +1,51 @@
+# Configuration Schema
+
+This document describes the configuration schema for `infctl-cli`.
+
+## Base Configuration (`base.json`)
+
+Example:
+```json
+{
+  "retry_delay_seconds": 3
+}
+```
+
+- `retry_delay_seconds` (integer): Delay in seconds before retrying failed steps.
+
+## Project Configuration (`config.json`)
+
+Project configuration fields are defined in the code and may include:
+- Project name
+- Directory paths
+- URLs
+- Port numbers
+- Log format
+
+Refer to the code for exact field names and types.
+
+## Pipeline Configuration (`pipeline.json`)
+
+Pipeline configuration is an array of steps. Each step:
+- `name`: Step name (string)
+- `function`: Function to call (string)
+- `params`: List of parameters (array of strings)
+- `retryCount`: Number of retries (integer)
+- `shouldAbort`: Whether to abort on failure (boolean)
+
+Example:
+```json
+[
+  {
+    "name": "ensure inf namespace exists",
+    "function": "k8sNamespaceExists",
+    "params": ["infctl"],
+    "retryCount": 0,
+    "shouldAbort": true
+  }
+]
+```
+
+## Notes
+- Example configuration files are provided as `.example` files in the repository.
+- All configuration fields must match those defined in the codebase; do not add undocumented fields.