Furnish schemas and release Relay 0.2.1

[devkyato]

What changed

I went through Relay once more from the perspective of somebody installing the public wheel rather than developing from a checkout. The missing piece was concrete integration contracts: the report declared schema version 2.0, but Relay could not yet hand an editor or CI job the schema itself.

This patch release:

• bundles JSON Schemas for report schema 2.0 and parsed relay.toml configuration;
• adds relay schema report and relay schema config, including atomic --output;
• validates real report/config data against both schemas in CI;
• includes valid and intentionally invalid configuration fixtures;
• documents compatibility, unknown-field, and versioning behaviour;
• makes the public GitHub wheel the primary installation path;
• incorporates the green pathspec>=0.12,<2 dependency update from Update pathspec requirement from <1,>=0.12 to >=0.12,<2 #11;
• removes tracked generated reports and ignores the documented local output names.

Oh! I kept Relay itself as the final configuration validator, because cross-field checks such as aggregate versus per-file limits should not be weakened just to fit a schema.

User impact

An installed Relay wheel can now furnish the exact schemas needed by editors and automation. Trying the README commands no longer leaves a dirty checkout, and current pathspec 1.x releases install without artificial resolver conflicts.

Validation

• 68 tests passed; one Windows symlink test skipped where the host cannot create symlinks
• Ruff lint and formatting passed
• strict Mypy passed
• pathspec 1.1.1 passed the full local suite
• wheel and source distribution built reproducibly
• clean-wheel pip check, version, schema, corpus JSON, timing summary, and doctor smoke tests passed
• installed report schema validated the real 15-file multilingual corpus report
• wheel inspection confirmed both schemas are packaged
• local Markdown links, JSON syntax, secret patterns, and staged diff passed

Closes #6