chore: prepare v0.2.0 release

[Achal13jain]

Summary

Prepares the v0.2.0 release after adding preflight validation.

This release updates package version metadata, changelog, README release wording, the static website, and the CLI version test. The website now presents vectormeta as a four-command workflow: scan, validate, fix, and hydrate.

Changes

• Bumped package version to 0.2.0.
• Updated CHANGELOG.md with the 0.2.0 - 2026-06-11 release entry.
• Updated README wording to highlight validation as part of the release.
• Updated the GitHub Pages site to show v0.2.0.
• Added validate to the visible website workflow.
• Updated the CLI version test.

Testing

python -m pytest
ruff check .
ruff format --check .
mypy vectormeta
python -m build

Release Notes (v0.2.0)

Added

• vectormeta validate CLI Command: Introduced for comprehensive preflight record checks prior to vector database upsert operations.
• Reusable Python API (validate_records()): Exposed programmatic interface to run validations natively within downstream pipelines.
• Structured Validation Reports: Output logs indicating specific error and warning severity thresholds.
• Preflight Verification Suite:
  Metadata payload size checks
  Missing and duplicate ID discovery
  Vector shape and dimension consistency validation
  Optional strict dimension matching via --dim flag
• Pinecone-specific metadata value constraints and rule validations

Checklist

• Release Checklist
• Version metadata updated.
• Changelog updated.
• README updated.
• Website updated.
• Tests pass locally.
• Package build succeeds locally.