feat(MODULE-014,MODULE-015): add correlation graph and timeline engine

[Atharva013]

Modules

• MODULE-014: Evidence correlation
• MODULE-015: Timeline engine

Summary

• Added a case-scoped correlation graph for evidence and normalized indicators.
• Added exact indicator correlation edges with evidence references.
• Added weak rule-based identity-domain relationships without treating them as confirmed identity matches.
• Added source-backed timeline extraction, timestamp normalization, deterministic ordering, deduplication, and conflict grouping.
• Updated module board/spec status for the intelligence batch.

Verification

• bash scripts/validate.sh
• 116 tests passed
• Ruff passed
• Mypy passed
• Module board validation passed

Security / Privacy

• Correlation graph requires explicit case scope.
• Added cross-case graph isolation test.
• Timeline events are created only from source-backed timestamps.
• No LLM-generated timestamps or inferred identity claims are treated as confirmed evidence.

Notes

• Temporal correlation hook is present but intentionally conservative in this MVP.
• Timeline output is presentation-neutral for later desktop/reporting integration.