feat(model-picker): sortable column headers — Model, Price, Context

- Add .ab-mp-col-headers bar between search and list with three
  clickable column headers: Model (sorts by name), Price in/out
  (sorts by input_price_per_m), Context (sorts by context_length)
- Track sortState at module level so preference persists across
  open/close; clicking same column toggles asc/desc
- Deprecated models always sink to bottom regardless of sort column
- Add CSS for .ab-mp-col-headers, .ab-mp-col-header, .ab-mp-sort-arrow,
  .ab-mp-col-active; widths mirror existing row flex layout so columns
  visually align with data

Bumps version 0.13.1 → 0.13.2

CHANGELOG.md

@@ -5,6 +5,11 @@ All notable changes to PRAutoBlogger will be documented in this file.
 Format follows [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project uses [Semantic Versioning](https://semver.org/).
 
+## [0.13.2] - 2026-04-24
+
+### Changed
+- Model picker: added sortable column headers (Model, Price, Context); clicking a header sorts the list ascending/descending; active column highlighted with sort arrow; sort preference persists while the picker is open.
+
 ## [0.12.3] — 2026-04-24
 ## [0.13.1] - 2026-04-24