feat(esp_lvgl_port): Add rounder_cb option for displays (BSP-705)

[nurdism]

• Version of modified component bumped
• CI passing (not sure how to run this)

This adds a config option to include a rounder cb for LVGL9, addresses #616

[CLAassistant]

All committers have signed the CLA.

[Copilot]

Pull Request Overview

This PR adds a rounder callback configuration option for LVGL9 displays in the ESP LVGL port component. The rounder callback allows customization of display area boundaries before invalidation events.

• Added lvgl_port_rounder_cb_t typedef and rounder_cb field to display configuration
• Implemented callback invocation in the display invalidate event handler
• Updated component version from 2.6.0 to 2.7.0

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
esp_lvgl_port_disp.h	Adds rounder callback typedef and configuration field for LVGL9
esp_lvgl_port_disp.c	Implements rounder callback invocation in invalidate event handler
idf_component.yml	Bumps component version to 2.7.0
README.md	Adds example usage of rounder_cb in display configuration
CHANGELOG.md	Documents the new rounder callback feature