refactor(sdk): relocate JSON-RPC example and runtime without edits

Move examples/jsonrpc-agent to examples/python-sdk-agent and packages/examples/jsonrpc-demo to packages/sdk/python-runtime while preserving every file byte-for-byte. The directory placement now reflects the example's Python-distribution role and the private runtime carrier's SDK ownership.

This commit deliberately keeps the old package names, commands, configuration, and snapshots inside their new directories. All 42 files are 100% renames; API/profile migration and naming changes follow separately so reviewers do not have to disentangle behavior from filesystem movement.