Update CHANGELOG for 0.9.0 and 0.10.0

[crtahlin]

Sub-issue of #114 (developer experience review).

Task

CHANGELOG.md is behind — last entry is 0.8.3, current version is 0.10.0. Add missing entries:

[0.10.0] - 2026-04-08

• Added: storageRef support in chain anchoring — set-storage-ref and lookup commands (Support storageRef in chain anchoring #116)

[0.9.0] - 2026-03-19

• Added: V2 contract parity — chain module rewrite for DataProvenance v2, state-based traversal, event cache fallback, merge transformations, --follow chain walking (Epic: V2 Contract Upgrade & MCP Chain Feature Parity #90)
• Added: Default signature verification on download (Make signature verification default on download #87)
• Added: Actionable insufficient funds UX for chain operations (Actionable insufficient funds UX for chain operations #89)
• Fixed: x402 402 response parsing for new gateway detail wrapper (Fix x402 402 response parsing for new gateway format (detail wrapper) #111)

Why

Accurate changelog is essential for tracking what changed between versions, both for humans reviewing releases and agents understanding project history.

[miles-on-nightshift]

Triage: classification: docs, priority: priority-medium

CHANGELOG gaps for 0.9.0 and 0.10.0 are user-facing trust signals. Worth doing before next release.

[miles-on-nightshift]

Triage: docs / priority: low

CHANGELOG update for released versions — hygiene task, no user impact.

Labels to add: documentation, priority-low