#3020 extension push: testing-completeness warns once per generated model (262 warnings in 25 extensions) with no way to mark a package generated

Problem

The testing-completeness review rule (src/domain/extensions/extension_review_rules.ts:192) checks for a sibling _test.ts per model file and warns once per model. On the swamp-extensions corpus that is 262 warnings across 25 extensions, 100% of generated models, which by design have no sibling test. In a generated package it drowns the one warning that matters.

Expected

• The rule reports once per extension ("N of M models have no sibling test"), not once per model.
• A generated: true manifest flag, or a codegen header in the file, silences it for that package or file.
• The warning text says which flag silences it.

Acceptance

• push --dry-run on a 25-model generated extension emits at most one testing-completeness warning, and none with generated: true.
• A hand-written extension with one untested model still warns, once.

Out of scope

Per-rule suppression with a reason is a separate issue in the same lane and goes after this one.

Source: the extension push assessment (2026-10-02, swamp 20261002.194016) and the Extension Push UX Plan, which groups this with its lane and order.