docs: remove alpha warning from apps pages except skills & agents (#19919)

## Summary
- Remove the \"Apps are currently in alpha\" warning from 8 pages under
`developers/extend/apps/` (getting-started, architecture/building,
data-model, layout, logic-functions, front-components, cli-and-testing,
publishing).
- Keep the warning on the Skills & Agents page only, and reword it to
scope it to that feature: \"Skills and agents are currently in alpha.
The feature works but is still evolving.\"

## Test plan
- [ ] Preview docs build and confirm the warning banner no longer
appears on the 8 pages above.
- [ ] Confirm the warning still renders on the Skills & Agents page with
the updated wording.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

packages/twenty-docs/developers/extend/apps/data-model.mdx

@@ -4,10 +4,6 @@ description: Define objects, fields, roles, and application metadata with the Tw
 icon: "database"
 ---
 
-<Warning>
-  Apps are currently in alpha. The feature works but is still evolving.
-</Warning>
-
 The `twenty-sdk` package provides `defineEntity` functions to declare your app's data model. You must use `export default defineEntity({...})` for the SDK to detect your entities. These functions validate your configuration at build time and provide IDE autocompletion and type safety.
 
 <Note>