OpenCode: re-verify OC-* and OC-SK-* rules against latest docs and refresh evidence

[avifenesh]

Summary

OpenCode rules docs were updated recently and include AGENTS/locals/fallback behavior and config guidance.

Source: https://opencode.ai/docs/rules

Need a source-of-truth refresh pass for OpenCode-related rules/evidence metadata.

Proposed Work

• Re-verify all OpenCode rule assumptions against current official docs.
• Update evidence.source_urls and evidence.verified_on for OC-* and OC-SK-* where needed.
• Confirm implementation + docs parity (rules.json and VALIDATION-RULES.md).
• Add/update tests only if behavior changed.

Acceptance Criteria

• OC-related rules have current verification dates and accurate source links.
• No stale/contradictory OpenCode claims remain.
• Parity and tests pass.

[avifenesh]

[DONE] Task Completed Successfully

PR: #574
Status: Merged to main
Commit: 35508af

Summary

• Re-verified all 9 OpenCode rules (OC-001 through OC-009, OC-SK-001) against current official docs
• Expanded KNOWN_TOP_LEVEL_KEYS with 9 missing keys from OpenCode's JSON schema
• Updated evidence.verified_on to 2026-02-27 for all 9 rules
• Added comprehensive test coverage at schema, validator, and fixture layers
• All 3766 tests pass, 0 failures

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This issue was automatically processed by AgentSys /next-task workflow.
Closing issue as the work has been completed and merged.