Allow to set branch mode in tinybird.config.json

[manumartinm]

This MR releases @tinybirdco/sdk version 0.0.78 and updates release notes to reflect Tinybird CLI 4.6.1 branch-management changes.

Changes

• Bumped package version to 0.0.78.
• Updated CHANGELOG.md with release notes for 0.0.78.

Documented CLI behavior updates (4.6.1)

• Migration from branch_data_on_create to branch_data_mode (legacy key now errors with explicit migration guidance).
• branch_data_mode now supports only last_partition as user-facing value.
• In local dev mode, branch data mode warnings appear only when explicitly configured.
• tinybird branch create / tinybird branch clear with --ignore-datasource now emit a deprecation warning and continue, instead of aborting.

Why

To keep TS SDK release notes and expected CLI behavior consistent for users managing branches through SDK-driven workflows.

[juliavallina]

MR title is not correct, right? can we add a MR description also?
And also, we should update docs/changelog/readme, right? how users are going to discover and use this new setting?