Phase 2: Schema + API + MCP (ABSORBED)

Goal: Add note_type + status columns to notes, create issues table, add repos page_note_id, update API routes and MCP tools with new query parameters.

Status: ABSORBED into plan-2026-03-01-note-decomposition

This phase was promoted to plan-2026-02-28-schema-api-mcp, which was subsequently absorbed into the decomposition plan. The decomposition plan adds parent_note_id + position columns alongside note_type + status, plus composition rendering. Issues table deferred to a future plan.