fix(client): preserve canonical format options in get_products

[bokelley]

Closes #1005.

What changed

• Parse get_products responses through the canonical GetProductsResponse model first.
• Preserve the existing legacy response projection as a fallback when canonical validation fails.
• Cache canonical product routes and attach an empty projection-diagnostics envelope for direct canonical responses.
• Add regression coverage for canonical-only products and for the legacy format_ids fallback.

Root cause

_canonicalize_get_products_result() parsed every response through LegacyGetProductsResponse before projection. The generated legacy ProductFormatDeclaration does not declare format_kind or params, so Pydantic discarded those canonical fields before project_legacy_product() saw them. Valid canonical-only products were then omitted with FORMAT_PROJECTION_FAILED diagnostics.

Impact

Python buyers using the primary ADCPClient.get_products() API now retain canonical format_options. Legacy-only sellers continue through the compatibility projector.

Validation

• make test: 6,200 passed, 41 skipped, 1 xfailed; 84.18% coverage
• make typecheck-all: passed (932 SDK source files plus strict adopter fixtures)
• make lint: passed
• File-scoped pre-commit suite: passed, including Bandit
• Live regression against Embedded Sales Agent:
  • released v7.0.0-rc: 2 wire products became 0 with four projection errors
  • this branch: both products and canonical image declarations were preserved