docs(quick-261015-w7f): docs since v0.1.14 and the Upgrading to 0.2 notes

- new setup/upgrading.md: version rule, the two 0.2 boot refusals with
  their fixes, behaviour changes, and what 0.2 adds since 0.1
- architecture module table lists all 28 modules
- WinterCMS map: cache and reorder are provided; rows for field types,
  sanitizing, singletons, API tokens, CORS, Turnstile, menu item types
- configuration keys for CORS profiles, api_docs, auth.cookie, turnstile
- index, setup intro and frontend page link the new topics

docs/setup/introduction.md

@@ -30,9 +30,12 @@ The data layer supports PostgreSQL only, and SummerCMS targets Go 1.27.
 
 ## How these docs are organised
 
-- **Setup** covers installation, configuration and the move from WinterCMS.
+- **Setup** covers installation, configuration, the move from WinterCMS and [Upgrading](upgrading.md) to a newer framework release.
 - **Architecture** explains the single binary, Go modules, the application lifecycle and how a request reaches your code.
-- **Plugins** covers registering a plugin, scheduling, extending other plugins and testing.
+- **Plugins** covers registering a plugin, scheduling, extending other plugins, menu item types and testing.
+- **Backend** covers the admin: controllers, forms and field types, lists and filters, relations, users and API tokens, settings and the admin SPA.
+- **Database** covers models, migrations, queries and pagination, relations, casts and validation, attachments and transactions.
+- **Services** covers configuration, events, routing, authentication, caching, rate limiting, storage, logging, mail, jobs, realtime, search, push and the other runtime services.
 - **Console** lists the `summer` tool's commands and the commands of every application binary, and shows how to write your own.
 - **API reference** has one page per framework module.