docs: complypack skill rename (pack-assessment → build-assessment) and test-driven workflow

[sonupreetam]

What Changed

The fix/unique-rego-namespaces branch on complytime/complypack introduces:

1. Skill rename: pack-assessment → build-assessment as the primary user-facing policy generation skill
2. Test-driven workflow: New test-driven-assessment internal skill generates human-reviewable test cases before any Rego policy is written. Users approve test scenarios first, then policy is generated to satisfy them.
3. New using-complypack skill: Establishes skill ordering and MCP grounding requirements — acts as the entry point for all compliance tasks
4. pack-assessment demoted to internal: Now marked user-invocable: false, orchestrated by build-assessment
5. Unique Rego namespaces: All generated .rego files now use unique package namespaces (e.g., package kubernetes.run_as_nonroot) instead of package main

Pages Needing Updates

• Any page referencing /comply:pack-assessment → update to /comply:build-assessment
• Any page referencing /comply:pack → update to /comply:build-assessment
• ComplyPack skill reference page (if exists) — add build-assessment, test-driven-assessment, using-complypack; mark pack-assessment as internal
• ComplyPack workflow documentation — describe the new test-first flow (test cases → approval → policy generation)
• ADR 018 documents the architectural decision

Why It Matters

Users following existing documentation to invoke /comply:pack-assessment directly will get an internal skill warning. The correct entry point is now /comply:build-assessment (single mode) or /comply:build-assessment batch (batch mode).