fix: restrict local file picker to verified ingestion extensions

[Wallgau]

I checked manually the file types that we support, here the ones ingested successfully:
documents: [
"txt",
"md",
"html",
"htm",
"adoc",
"asciidoc",
"asc",
"pdf",
"docx",
],
spreadsheets: ["csv"],
}

Scope
Updates are limited to:
--> frontend/components/knowledge-dropdown.tsx
--> docs/docs/core-components/ingestion.mdx

What changed
knowledge-dropdown.tsx

• SUPPORTED_FILE_TYPES / SUPPORTED_EXTENSIONS (local file picker + folder ingest filter) now only allow extensions that were verified to ingest successfully in your tests:
• documents — .txt, .md, .html, .htm, .adoc, .asciidoc, .asc, .pdf, .docx
• spreadsheets — .csv
• Types you marked as failing (e.g. .mdx, .xml, code, JSON/YAML, etc.) are not in the picker/filter.

ingestion.mdx

• “Supported file types” section updated to match that verified list.
• Clarifies that the chat/local picker only offers these until other types are confirmed, and that cloud connectors may still differ.

[edwinjosechittilappilly]

should we add it as comments for Future TODO?

[edwinjosechittilappilly]

LGTM

[edwinjosechittilappilly]

@Wallgau can you create a same PR for Main branch also?

[github-actions]

Build successful! ✅
Deploying docs draft.
Deploy successful! View draft