[TASK] Content Drive: Add a FILEASSET base-type → content-type resolution strategy #36279

Description

Content Drive's upload flow (PR #36243, issue #35575) lets the user choose Asset vs File before uploading. Semantically these are base types, but the frontend currently sends the content type variable (dotAsset / FileAsset) because base-type → content-type resolution only works for DOTASSET on the backend.

Where it breaks for FILEASSET:

• BaseTypeToContentTypeStrategyResolver (dotCMS/src/main/java/com/dotcms/contenttype/business/BaseTypeToContentTypeStrategyResolver.java) registers a strategy only for BaseContentType.DOTASSET (DotAssetBaseTypeToContentTypeStrategyImpl, which uses DotAssetAPI.tryMatch to pick the best dotAsset content type by mime type). There is no FILEASSET strategy.
• ContentHelper.tryToSetContentType only sets the contentlet's content type when a strategy exists for the given base type; otherwise it is skipped.
• MapToContentletPopulator.getContentTypeInode resolves the type solely from structureInode / structureName / contentType — there is no fallback from baseType.
• Net result: firing the NEW workflow action with only baseType: FILEASSET (no contentType) fails with "The content type or base type, is not set or is invalid."

Latent bug to fix along the way:

• BaseTypeToContentTypeStrategyResolver.subscribe(...) ignores its baseContentType argument and always does builder.put(BaseContentType.DOTASSET, strategy), so a FILEASSET strategy can't even be registered via subscribe today.

Acceptance Criteria

• Register a FILEASSET base-type → content-type resolution strategy so that firing the NEW workflow action with baseType: FILEASSET (no explicit contentType) resolves to the appropriate File Asset content type (default/system FileAsset, or best match if multiple FILEASSET content types exist).
• Fix BaseTypeToContentTypeStrategyResolver.subscribe(...) so it registers the strategy under the passed baseContentType instead of always DOTASSET.
• Add coverage (unit/integration) for resolving FILEASSET (and a regression test for the subscribe fix).
• Once this lands, the Content Drive frontend ([TASK] Content Drive: Upload button — Asset vs File type selection #35575) can send the base type for both Asset and File instead of the content type, matching what the upload dialog actually asks.

Priority

Medium

Additional Context

• Parent epic: [EPIC] Content Drive: Upload #35436
• Follow-up from PR feat(content-drive): prompt Asset vs File on upload (#35575) #36243 / issue [TASK] Content Drive: Upload button — Asset vs File type selection #35575 (frontend ships sending content type as the working approach; this task enables the cleaner base-type approach).
• Reference for the working DOTASSET strategy: DotAssetBaseTypeToContentTypeStrategyImpl + DotAssetAPIImpl.tryMatch.