fix: improve streaming FVDL filter support

[kireetivar]

The streaming parser now exposes the expected filterable data more consistently with the regular FPR path, including analysis type and other streamed attributes that were previously missing or mapped incorrectly.

Changes:

• populate and expose analysisType during streaming FVDL parsing
• add support for additional streamed filter attributes and metadata-backed values
• restore legacy filter aliases for compatibility with existing filter expressions
• fix audit-state merging so default pending-review values are not treated as audited
• fix source and sink context selection for multi-trace vulnerabilities
• add focused regression tests for metadata parsing, filter behavior.