chore: bump planner_v3 version to 3.8.1

feat: add iframe auto-resize script to planner embeds and update parallel execution documentation

docs: clarify parallel subagent file management warning in planner_v3.py

refactor: modularize planner tool specifications and add environment placeholder resolution utilities

feat: improve MCP session header resolution and prevent side effects with extra_params shallow copying

docs: update README and planner_v3.py metadata to, parallel execution, and improved agentic capabilities.

refactor: decouple pipe metadata from wide metadata to improve context handling in planner functions

refactor: update context structure to include planner_info, improve base URL resolution, and wire engine to emitter

refactor: introduce PlannerContext and StatePersistence classes, and update subagent history keys to JSON arrays for robustness

refactor: update subagent status reporting to use task-specific identifiers and consolidate UI feedback messages

fix: escape JSON attributes in tool call HTML and standardize result extraction for v3.15 parity

chore: bump planner_v3 version to 3.7.0

feat: implement signature-based context injection and embed emission for planner tools

refactor: implement QueueEmitter with throttling, add MCP log filtering, and optimize model workspace resolution

feat: add MCP connection isolation, workspace model parity, and extended tool resolution helpers to planner_v3.py