docs(changelog): v0.1.4 release notes

[niceclat]

Summary

Adds the CHANGELOG entry for v0.1.4 covering the five features merged this cycle:

• ValkeyStateStore (feat(attack_chains): ValkeyStateStore — cross-process multi-step chain detection (0.1.4) #38)
• Trust Assessment orchestrator (feat(assessment): Autonomous Systems Trust Assessment orchestrator (5 pillars, live PG-tested) #39)
• Delegation-graph-aware cross-agent correlation (feat(attack_chains): delegation-graph-aware cross-agent correlation (depends on #38) #40)
• DAG step grammar (feat(attack_chains): DAG step grammar — diamond / AND-join patterns (depends on #38, #40) #41)
• Sigma -> KYA rule adapter (feat(attack_chains): Sigma rule adapter — SigmaHQ interop (depends on #38, #40, #41) #42)

pyproject.toml was already bumped to 0.1.4 in #38; this only adds the CHANGELOG narrative for the release.

Test plan

• CHANGELOG renders correctly
• No code changes — CI green is sufficient