Implement Coherent Tagging Strategy Across ADK Repositories

The Google ADK project includes several language-specific repositories (`adk-python`, `adk-go`, `adk-java`) which integrate the **web interface files** from this repository (`adk-web`).

Periodically, the files generated by `adk-web` are copied and committed into the dependent repositories. This integration is typically noted via generic commit messages like "Update ADK Web to match main branch."

## The Problem

When reviewing a dependent repository (e.g., `adk-python`), it is **not currently possible** to easily determine **which specific version or commit of `adk-web`** was used for the latest update. Since these files define the ADK web interface, this lack of clear version mapping makes it difficult to:

* **Audit** the exact state of the integrated web components.
* **Track** potential bugs in the web UI back to a specific `adk-web` change.
* **Verify** if a particular web-related feature or fix from `adk-web` has been pulled into the dependent language libraries.

## The Proposed Solution

We request the implementation of a strategy for version tagging that ensures traceability between the repositories:

1. **Tagging `adk-web`:** Use clear, sequential **version tags** (e.g., `v1.2.3`) on the `adk-web` repository for each version update that is intended for integration.
2. **Referencing Tags in Dependent Repos:** When the generated files are committed to repositories like `adk-python`, `adk-go`, and `adk-java`, the accompanying commit message or an update file (e.g., a simple `ADK_WEB_VERSION` text file) should explicitly reference the **exact tag from `adk-web`** that was integrated.
* *Example Commit Message:* `Update ADK Web UI files to tag **v1.2.3**`

## Benefits

Implementing this coherent tagging and referencing strategy would significantly improve the maintainability, transparency, and traceability of the ADK project ecosystem, particularly for debugging and auditing the static web components.