chore(demo-web): update default LLM models

[kimhongyeon]

Affected Package(s)

• @heripo/pdf-parser
• @heripo/document-processor
• @heripo/model
• @heripo/logger
• @heripo/shared (internal)
• demo-web
• docs
• Other (root configs, CI, etc.)

Summary

This PR updates the demo web upload form defaults to use a newer local Gemma model for language detection and caption parsing. The change keeps the processing configuration aligned with the intended LLM setup for OCR language hints and post-processing tasks.

Changes

• Updated DEFAULT_FORM_VALUES.languageDetectionModel in apps/demo-web/src/features/upload/types/form-values.ts from lmstudio/gemma-4-e4b-it-mlx to lmstudio/gemma-4-26b-a4b-it-mlx.
• Updated DEFAULT_FORM_VALUES.captionParserModel in apps/demo-web/src/features/upload/types/form-values.ts from lmstudio/gemma-4-e4b-it-mlx to lmstudio/gemma-4-26b-a4b-it-mlx.

Breaking Changes

• None
• If any, describe migration steps:

Checklist

• I followed the Code of Conduct (see CODE_OF_CONDUCT.md)
• I ran: pnpm lint pnpm typecheck pnpm build pnpm test
• Tests added/updated; coverage remains 100%
• Docs/README updated if needed
• No external side effects (network/file/process/time) in tests — use mocks

Related Issues

Closes #