Convert readable range inputs

[chubes4]

Summary

• Treat input[type=range] as a readable static form control so standalone sliders convert to paragraph summaries instead of unsupported fallback metadata.
• Include current value plus min/max/step bounds in the readable summary.
• Add contract coverage proving standalone range inputs avoid unsupported_element fallbacks.

Fallback cluster evidence

From /var/folders/lr/c_cmmt7s0592m4njz99v5yb40000gn/T/opencode/ssi-finding-packets-0.1.15.json:

• canvas_requires_runtime: 18 findings, clustered around native canvas runtime surfaces in 41-generative-art-studio, 43-interactive-space-explorer, and saveweb2zip-com-liquidbonsai-com.
• script_requires_runtime: 16 findings, first page-level runtime scripts across multiple fixtures.
• generated_document_contains_core_html: 14 findings, all canvas-backed core/html materializations.
• form_requires_runtime: 6 findings, runtime form submissions in 40-job-board and mockup.
• unsupported_element: 6 findings, all duplicate reporting for three standalone input[type=range] controls in 41-generative-art-studio/index.html.

Expected matrix impact

• Removes the three underlying standalone range-input unsupported fallbacks from fixture 41-generative-art-studio/index.html; packet duplication should reduce the six unsupported_element findings.
• Does not suppress diagnostics. Canvas, script, and runtime form findings remain truthful runtime fallbacks.

Verification

• php php-transformer/tests/contract/run.php
• composer test:canonical --working-dir=php-transformer
• Manual fixture check: transforming fixtures/websites/41-generative-art-studio/index.html now reports only canvas_requires_runtime|canvas => 7 and script_requires_runtime|script => 2, with no unsupported_element|input fallbacks.

AI assistance

• AI assistance: Yes
• Tool(s): openai/gpt-5.5 via OpenCode
• Used for: fallback packet clustering, implementation, tests, and verification.