feat(coding-agent): add pluggable operations for remote tool execution
Adds optional operations parameter to create*Tool functions enabling
delegation to remote systems (SSH, containers, etc.):
- ReadOperations: readFile, access, detectImageMimeType
- WriteOperations: writeFile, mkdir
- EditOperations: readFile, writeFile, access
- BashOperations: exec (with streaming, signal, timeout)
Add ssh.ts example demonstrating --ssh flag for remote execution.
Built-in renderers used automatically for overrides without custom renderers.
fixes #564
9ed88646a8