[LFX] Explore localization team status visibility reporting

# What would you like to be added?
I would like to explore a lightweight reporting helper for localization team status visibility.

The goal is to provide a simple way to see, at a glance, which localized files are most likely to need review based on better outdated-content signals, so localization maintainers can prioritize update work more effectively.

Rather than centering this work on Git recency alone, I want to explore a visibility/reporting layer that can eventually consume stronger signals from the content-based outdated detection work in #54896.

Possible initial prototype scope:
- accept a target localization language (for example ko)
- compare files that exist in both content/en/ and content/ko/
- summarize files that are most likely to deserve review based on available outdated-content signals
- output a ranked or grouped summary to help maintainers identify which files may deserve attention first
- keep the implementation lightweight and easy to maintain

This issue is part of the broader LFX localization workflow effort: https://github.com/kubernetes/website/issues/54075

# Why is this needed?
Today, localization contributors can inspect specific files or directories with existing tools such as `scripts/lsync.sh`, which is useful when working on a known target file.

However, there is still a separate workflow need: team-level visibility.

Examples of visibility questions include:
- Which files in our localization set are most likely to need review?
- Which areas should we review first in the next update cycle?
- How can maintainers quickly get a rough status snapshot for planning or reporting?

A lightweight visibility-oriented helper could support these workflows, especially if it is built on top of better outdated-content signals rather than relying only on timestamps or commit chronology.

This issue also builds on earlier exploration of localization reporting in #45844, but the goal here is not to continue with a Git-recency-based direction as the main approach. Instead, the intention is to explore a smaller visibility helper that can eventually align with the stronger content-based outdated detection work being explored in #54896.

In particular, this direction is intended to:

- keep the scope smaller and easier to review
- avoid claiming semantic or content-level freshness detection beyond what the underlying signals can support
- complement existing workflows such as `scripts/lsync.sh`, rather than replace them
- allow the reporting/visibility layer to evolve separately from the detector implementation details

This work is also separate from content-based outdated detection efforts. More advanced detection approaches can continue in their own workstream, while this issue focuses on a smaller visibility/reporting layer.

# Scope
Initial exploration scope:
- single-language reporting per run
- visibility/reporting based on available outdated-content signals
- ranked or grouped text output suitable for local maintainer use
- minimal implementation complexity
- easy to test and review

# Non-goals
This issue is not intended to:
- define the full outdated-content detection algorithm itself
- replace existing scripts
- introduce AI-, embedding-, or semantic-based comparison directly in this reporting layer
- enforce synchronization rules
- define a universal workflow for all localization teams

/area localization


Start by reading scripts/lsync.sh and inspecting the corresponding files under content/en/ and content/ko/. Review the outdated-content signal work in #54896 and the earlier reporting exploration in #45844 before defining the prototype boundary. Done should be a tested, lightweight single-language report with ranked or grouped text output, without implementing the detector itself.

Written by the indexing model from the issue text.