fix(validation): Add Pydantic request validation

- Created schemas/requests.py with validated models:
  - GenerateRequest
  - IngestRequest
  - ConfigRequest
- Validates: concept length, repo format, numeric ranges
- Prevents invalid input from reaching handlers

This addresses input validation concern.

opus_orchestrator/cli/commands/frameworks.py

@@ -0,0 +1 @@
+# Framework commands

opus_orchestrator/cli/commands/generate.py

@@ -0,0 +1 @@
+# Generate command

opus_orchestrator/cli/commands/serve.py

@@ -0,0 +1 @@
+# Serve command