Prepare for v1.0.0

[Marenz]

• Reset release notes for next release
• Update freunz-api-dispatch dependency to 1.0.0

[Copilot]

Pull Request Overview

This PR prepares the project for v1.0.0 release by updating dependencies and resetting release notes for the next development cycle.

• Updated frequenz-api-dispatch dependency from release candidate to stable v1.0.0
• Reset release notes by removing completed features and adding placeholder comments

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
pyproject.toml	Updated frequenz-api-dispatch dependency version from 1.0.0-rc3 to 1.0.0 across all dependency groups
RELEASE_NOTES.md	Cleared previous release notes and added placeholder comments for future features and bug fixes

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}