docs(readme): add Companion tools section linking OpsMind and the compliance dashboard

[Pawansingh3889]

What changed

Added a "Companion tools" section to the README, between the Links section and "Why Does This Exist?". Cross-links sql-sop to its two companion repos:

• OpsMind — on-prem NL-to-SQL AI assistant; uses sql-sop as the static safety layer for every LLM-generated query before execution.
• Manufacturing Compliance Dashboard — live BRC/HACCP dashboard for manufacturing data; same read-only safety model.

Also pointed readers at the dbt-aware rule pack ADR (DBT001+) as the broader roadmap.

Related issue

In flight — Innovate UK AKT 6 application (deadline 15 July 2026) for OpsMind multi-plant validation. sql-sop is the safety-layer companion tool referenced in the application; cross-linking strengthens the platform narrative.

If this adds or changes a rule

N/A — docs-only.

Tests

• pytest -q unaffected (no test changes)
• ruff check . unaffected (no code changes)

Checklist

• One logical change per commit
• Conventional commit style (docs(readme):)
• Internal links verified
• No CHANGELOG.md entry — README polish, not user-facing behaviour