fix: pass editor content for JetBrains autocomplete to fix large file truncation

[praneethb7]

Description

Fixes #12390 : autocomplete showing wrong/static prefix & suffix on files larger than ~3000 lines in JetBrains.

Root cause: FileUtils.readFile() caps file content at 100,000 characters. For large files this truncates the content always from line 0, so the core computed the same wrong prefix/suffix regardless of cursor position.

Fix: Pass editor.document.text (full live in-memory content, no size limit) as manuallyPassFileContents in the autocomplete request, exactly mirroring what the VS Code extension already does via openTextDocument.getText(). When manuallyPassFileContents is present, the core skips the disk/file read entirely.

Changes:

• CompletionService.kt : added optional fileContents parameter to interface
• ContinueCompletionService.kt : passes manuallyPassFileContents in the request payload
• ContinueInlineCompletionProvider.kt : reads editor.document.text and passes it to the service

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Checklist

• I've read the contributing guide
• The relevant docs, if any, have been updated or created
• The relevant tests, if any, have been updated or created

Screen recording or screenshot

N/A: The fix mirrors the existing VS Code implementation and was verified by code inspection.

Tests

No new tests added. The fix mirrors the VS Code extension's approach (openTextDocument.getText()).

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Summary by cubic

Fixes wrong/static autocomplete prefixes and suffixes in JetBrains for large files by sending the full in-memory editor text instead of reading from disk. Also updates docs to cover local config profiles and dynamic model fetching in the UI.

• Bug Fixes
  • Pass editor.document.text as manuallyPassFileContents so the core skips disk reads and uses the full file content.
  • Add optional fileContents to CompletionService and wire it through ContinueCompletionService and ContinueInlineCompletionProvider.
  • Update unit test mock to match the new getAutocomplete signature.

^{Written for commit bccf247. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 7 files