README still describes the web app as the legacy 12-lesson track

[cf-x]

Problem

The root README still describes the current web/ app as part of the legacy 12-lesson track in several places:

• the Version Status section groups web/ with docs/ and agents/
• the Web Platform section says the app renders docs/ s01-s12
• the project tree labels web/ as rendering the legacy docs track

That description became stale after the Web curriculum was migrated to the root-level chapters.

Current behavior

web/package.json runs the extraction script before both development and production builds. The extractor discovers root-level sNN_* directories and, whenever they exist, builds versions and documentation from that track. In the current repository this produces 20 versions (s01 through s20) and 60 localized documents.

The legacy agents/ and docs/ directories are still correctly described as the older 12-lesson track; only the statements that include the current Web app are outdated.

Impact

Readers can be incorrectly led to avoid the Web app or expect its chapter numbering and content to differ from the canonical root-level course, even though the app now presents the current 20-chapter track.

Proposed update

Update the README references to state that the Web app renders the current root-level s01-s20 course. Keep the legacy track description and legacy-to-current mapping for agents/ and docs/ unchanged.