walnut-core-internals

# Core Layer — Implementation Details Detailed internals for `src/core/`. For architecture overview, see project `CLAUDE.md`. ## Task Model Details ### Task text fields (5-field model) Each task has `description` (what & why — pre-action context, user-set), `summary` (TL;DR of progress — AI-maintained), `note` (detailed markdown blob — evolving, append via `addNote()` or replace via `updateNote()`), and `conversation_log` (append-only markdown log of user↔agent interactions, auto-managed by the chat handler via `appendConversationLog()`). The conversation_log is automatically appended server-side after every chat turn where a task is focused — each entry has a `### YYYY-MM-DD HH:MM` timestamp heading followed by `**User:**`/`**AI:**` summaries (truncated to 150/200 chars). The field is optional, starts as `undefined`, and is created on first interaction. Migration from the old `notes: string[]` is handled by `migrateNotesToFields()` in `task-manager.ts`. MS To-Do sync: all fields combine into a structured body (`description\n\n---\n\n## Summary\n...\n\n## Notes\n...\n\n## Conversation Log\n...`) via `composeMsTodoBody()`/`parseMsTodoBody()` in `src/integrations/microsoft-todo.ts`. External sync plugins: each plugin decides how to map these fields to its platform (e.g., description field, comment body, etc.). See the plugin's own documentation for details. Conversation_log is tail-truncated (recent entries preserved) in Task Context (400 chars), session context (300 t...