Fix OB1 Agent Memory ClawHub install metadata

[justfinethanku]

Summary

• bump OB1 Agent Memory OpenClaw plugin to 0.1.6
• mark the OpenClaw peer dependency optional so npm does not install a nested OpenClaw package before host SDK symlink repair
• update install docs and release notes for the ClawHub one-line path plus the 2026.5.2 tarball fallback

Verification

• npm run schema:check
• npm run build
• npm pack --dry-run
• local 0.1.6 tarball install on OpenClaw 2026.5.2, 2026.5.7, and 2026.5.20
• published @natebjones/ob1-agent-memory@0.1.6 to ClawHub
• live clawhub install on OpenClaw 2026.5.7 and 2026.5.20
• live tarball fallback install on OpenClaw 2026.5.2
• runtime inspect shows version 0.1.6, all seven openbrain_* tools, and no diagnostics

Linear: NAT-999

[justfinethanku]

Review checkpoint before merge:

• Diff is scoped to OB1 Agent Memory package metadata and install docs/release notes.
• The functional package change is peerDependenciesMeta.openclaw.optional = true, while keeping openclaw in peerDependencies so OpenClaw can still create the host SDK symlink.
• This prevents npm from materializing a nested node_modules/openclaw during archive installs on newer npm/OpenClaw combinations.
• Verified local package checks and live ClawHub installs for @natebjones/ob1-agent-memory@0.1.6.

No blocking review findings from this pass.