Fix wording on patch-family upgrade pages (4.2.2.x, 4.3.1.x)

[trikimiki]

Description

Summary

• Commit a2373cdcb77510b24a4de27b744e1f394e623f7d:
  • The 4.3.1.2 upgrade page said "applicable for ... any 4.3.1 patch" and "from version 4.3.1.x". But anyone on a 4.3.x release can use those steps - now both spots read 4.3.x.
  • Done via a new optional patchableFrom field on UpgradeVersion, set on the three 4.3.1.x entries. Templates fall back to baseVersion when unset, so every other upgrade page renders byte-identical to before.

• Commit 112b33c207786ee4d3927bc160d1e6848c1acd5b:
  • Previously every patch in a family said "Upgrading ... to latest 4.2.2 (4.2.2.X)" — 4.2.2.2 and 4.2.2.1 both claimed "latest". Now only the actual newest carries it, and reads "Upgrading ... to 4.2.2.2 (latest 4.2.2 patch)"; older patches drop the qualifier.
  • Done via a derived LATEST_PATCH_VERSIONS set in the model (no per-entry flag to maintain).

Type of change

• New / updated documentation page (src/content/docs/**)
• Shared include file (src/content/_includes/**)
• Component, layout, or styling change (src/components/**, src/styles/**)
• Landing / use-case / case-study page (src/pages/**, src/data/**)
• Redirects (src/data/redirects.ts)
• Version bump / release (see release skill)
• Build, CI, scripts, or tooling
• Other (please describe)

Upgrade-instruction page templates (src/pages/docs/.../upgrade-instructions/[platform]/[familySlug].astro, CE + PE) and the upgrade-version data model (src/models/upgrade-instructions.ts).

Affected products

PE + CE upgrade docs

Related issues

• Closes #

Checklist

• pnpm check passes (Astro / TypeScript)
• pnpm lint:eslint passes
• pnpm lint:slugcheck passes (required if pages were added/renamed/moved across languages)
• pnpm lint:linkcheck passes locally — required to merge; run it before requesting review (use pnpm lint:linkcheck:nobuild if you already ran a build)
• Renamed/removed pages have a redirect in src/data/redirects.ts, and pnpm generate:redirects was run
• No hardcoded versions — values come from src/data/versions.ts
• Screenshots attached for visual changes