feat: add OpenProse plugin skills

extensions/open-prose/skills/prose/examples/22-error-handling.prose

@@ -0,0 +1,51 @@
+# Error Handling Example
+# Demonstrates try/catch/finally patterns for resilient workflows
+
+# Basic try/catch for error recovery
+try:
+  session "Attempt to fetch data from external API"
+catch:
+  session "API failed - use cached data instead"
+
+# Catch with error variable for context-aware handling
+try:
+  session "Parse and validate complex configuration file"
+catch as err:
+  session "Handle the configuration error"
+    context: err
+
+# Try/catch/finally for resource cleanup
+try:
+  session "Open database connection and perform queries"
+catch:
+  session "Log database error and notify admin"
+finally:
+  session "Ensure database connection is properly closed"
+
+# Nested error handling
+try:
+  session "Start outer transaction"
+  try:
+    session "Perform risky inner operation"
+  catch:
+    session "Recover inner operation"
+    throw  # Re-raise to outer handler
+catch:
+  session "Handle re-raised error at outer level"
+
+# Error handling in parallel blocks
+parallel:
+  try:
+    session "Service A - might fail"
+  catch:
+    session "Fallback for Service A"
+  try:
+    session "Service B - might fail"
+  catch:
+    session "Fallback for Service B"
+
+session "Continue with whatever results we got"
+
+# Throwing custom errors
+session "Validate input data"
+throw "Validation failed: missing required fields"