docs(codegen): SP-1a implementation plan — TS declarative template-codegen

8-task TDD plan for the TS reference increment: perPackage helper + perModel
rename; neutral structural data-dict builder; output-pattern expander; scope
walks wired into templateGenerator; JSON template-spec + schema (the CLI-port
contract); the template-codegen-conformance corpus + TS gate. Grounded in the
real metadata accessors; self-reviewed against the spec.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LuZWKnWzYGVnESijL7uuky

Author: dmealing