Vega-Lite format parity for tables and Python formatters

Problem

Implement or reuse Python number/date formatting aligned with Vega-Lite format and formatType so style.columns value options match axis and chart labeling. Share logic between SVG charts and table renderers.

Context

• Tables and charts should format the same values the same way, but today they rely on different paths.
• Vega-Lite already defines a strong formatting vocabulary that Dataface chart labels use.
• Table formatting work will be confusing if authors learn one format model for axes and another for cells.

Possible Solutions

• A - Keep a table-specific formatter model and document the difference from charts: explicit, but inconsistent.
• B - Reimplement a rough subset of Vega-Lite formatting just for tables: doable, but duplicative.
• C - Recommended: reuse or wrap one shared Python formatting layer aligned to Vega-Lite format and formatType semantics across chart and table surfaces.

Plan

1. Inventory the formatting options already used in chart rendering and docs.
2. Design the shared formatter interface and table schema language around that vocabulary.
3. Implement parity coverage for representative number and date cases across chart and table output.
4. Add regression tests and docs that prove author-facing format consistency.

Implementation Progress

QA Exploration

• [ ] QA exploration completed (or N/A for non-UI tasks)

Review Feedback

• [ ] Review cleared