Release Threadnote 4.0.2

[Kashkovsky]

Summary

• bump the standalone release version from 4.0.1 to 4.0.2
• add versioned release notes covering every user-visible change since 4.0.1
• include the post-pull graph latency fix, MCP canonical-read compatibility, dependency/security refreshes, and release evidence improvements

Release audit

• reviewed all commits after v4.0.1 through the merged graph-query fix in Avoid blocking graph queries after clean pulls #109
• reviewed the latest retained production-large evidence attempt for v4.0.1; it failed provenance validation before measurement, which the already-merged stable-tag fix corrects for this tag
• confirmed the release workflow owns immutable GitHub release creation after the version tag is pushed

Checks

• bun --bun vitest run test/unit/release_notes.test.ts test/unit/publish-workflow.test.ts test/unit/ci-workflow.test.ts test/unit/benchmark-workflow.test.ts test/unit/code-graph.release-evidence.test.ts test/unit/website-release-boundary.test.ts (56 tests)
• bun run precommit (lint, formatting, 186 files / 1,777 tests)
• commit hook (lint, formatting, 186 files / 1,777 tests)