[Docs Agent] Release of Docs Agent v 0.3.5.

Description of the change

agent runtask command: Run tasks defined in .yaml files, for example, generating release notes based on commit messages.
Session Management: Start and maintain sessions using --new and --cont flags with the helpme and tellme commands.
CLI Command Refactoring: The CLI is more modular and easier to extend with new commands.
Web App Mode Updates: A new widget-pro mode is added as an iFrame-friendly template.
Bug Fixes: Various bug fixes related to flags, UI, and file handling.

New features

Choose one: (Feature request)

[ X] I have performed a self-review of my code.
[ X] I have added detailed comments to my code where applicable.
[ X] I have verified that my change does not break existing code.
[ X] My PR is based on the latest changes of the main branch (if unsure, please run git pull --rebase upstream main).
[ X] I am familiar with the Google Style Guide for the language I have coded in.
[ X] I have read through the Contributing Guide and signed the Contributor License Agreement.