Refresh product record docs for the 1.2.0 release line

[codeforester]

Finding

The current release is 1.2.0, but maintained product record docs still say the Base era reviewed is 1.1.0. The product assessment explicitly says it should be reviewed during each minor release line.

Evidence

• VERSION is 1.2.0.
• .ai-context/STATUS.md says Base 1.2.0 is the current release and the v1.2.0 milestone is complete.
• docs/product-requirements.md still says Base era reviewed: 1.1.0.
• docs/product-assessment.md still says Base era reviewed: 1.1.0 and its maintenance policy includes each minor release line.

Acceptance Criteria

• Review and update docs/product-requirements.md for the 1.2.0 release line.
• Review and update docs/product-assessment.md for the 1.2.0 release line.
• Update any adjacent record docs that explicitly claim the current assessed era is 1.1.0 when they should reflect 1.2.0.
• Avoid marketing drift; keep claims tied to current implementation, docs, tests, and known adoption evidence.

Suggested Validation

• git diff --check
• Optional: run basectl prompt product-self-review before revising the assessment.