SubMiner/backlog/tasks/task-20.2 - Add-renderer-to-main-IPC-contract-for-measured-overlay-content-bounds.md

id, title, status, assignee, created_date, updated_date, labels, dependencies, parent_task_id, priority

id	title	status	assignee	created_date	updated_date	labels	dependencies	parent_task_id	priority
TASK-20.2	Add renderer-to-main IPC contract for measured overlay content bounds	To Do		2026-02-12 08:47	2026-02-12 09:42			TASK-20	medium

Description

Add renderer-to-main IPC for content measurement reporting, so main process can size each overlay window from post-layout DOM bounds.

Acceptance Criteria

• #1 Preload exposes a typed API for reporting overlay content bounds with layer metadata.
• #2 Main-process IPC handler validates payload shape/range and stores latest measurement per layer.
• #3 Renderer emits measurement updates on subtitle, mode, style, and render-metric changes with throttling/debounce.
• #4 No crashes or unbounded logging when measurements are missing/empty/invalid; fallback behavior is explicit.