Runtime tools now register on-demand rather than at startup:
- get_runtime_mode(): check mode status and available capabilities
- enable_runtime_mode(): dynamically register 36 runtime tools
- disable_runtime_mode(): remove runtime tools when not needed
At startup, only 33 design-time tools are registered. When runtime mode
is enabled, tool count increases to 69. This reduces context usage
significantly when only doing flowgraph design work.
Uses FastMCP's add_tool/remove_tool API for dynamic registration,
following MCP spec's notifications/tools/list_changed pattern.