test(compiler): enforce preview render parity

[jrusso1020]

What

Add a normalized preview/render semantic parity corpus.

Why

Preview and render compilation had accumulated one-sided fixes in timing, bootstrap, styles, URLs, and manifests.

How

Define a neutral parity contract and run shared fixtures through core preview and producer render compilation.

Test plan

• core html parity and producer htmlCompiler parity suites
• Stack-wide lint, format, build, typecheck, and relevant integration gates

[jrusso1020]

• refactor(repo): resolve changed-code audit #2174
• test(engine): isolate peer abort regression #2173
• refactor(cli): decompose render phases #2172
• refactor(cli): centralize process lifecycle #2171
• fix(cloudrun): publish adapter contract #2170
• test(repo): execute packed subpaths #2169
• refactor(repo): centralize package subpaths #2168
• refactor(core): own edit protocol contract #2167
• test(compiler): enforce preview render parity #2166 👈 (View in Graphite)
• refactor(studio): gate SDK operation families #2165
• refactor(studio): gate Acorn writer migration #2164
• refactor(producer): make capture plans immutable #2163
• refactor(producer): unify render requests #2162
• refactor(engine): type capture failures #2161
• refactor(engine): manage child process lifecycles #2160
• refactor(engine): add fingerprinted browser leases #2159
• refactor(render): centralize execution ownership #2158
• refactor(core): unify composition contract #2157
• fix(studio): enforce optimistic file concurrency #2156
• fix(studio): make sdk cutover transactional #2155
• fix(render): publish artifacts atomically #2154
• fix(render): surface structured outcomes #2153
• fix(player): own connection and media resources #2152
• fix(core): preserve runtime transport contract #2151
• fix(player): version runtime protocol #2150
• test(repo): verify packed consumers #2149
• test(repo): enforce workspace contracts #2148
• fix(core): enforce strict runtime safety #2147
• test(producer): gate source tests by execution lane #2146
• fix(core): make timing masks safe for source loaders #2145
• chore(repo): forbid tracked generated artifacts #2144
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.

[miguel-heygen]

Fresh exact-head review at f0956e594.

• packages/core/src/compiler/htmlParityContract.ts:44 normalizes legacy/current timing, canonicalizes nested variable JSON, collapses embedded and project-relative assets into the same local semantic class, and keeps stable identities for compositions, timed elements, and resources.
• packages/producer/src/services/htmlCompiler.parity.test.ts:30 runs the same authored fixtures through the actual Core preview bundler and Producer render compiler before comparing structured contracts; this is a genuine cross-pipeline assertion, not a shared snapshot.
• packages/core/src/compiler/htmlParityContract.test.ts:4 independently pins the extractor against literal timing, track, variable, and resource expectations, reducing the risk of both pipelines passing through a broken normalizer.

I read the complete four-file diff, traced both compiler entry points, checked existing feedback and threads, verified the exact merge base, and pulled exact-head required CI. No blocker found. The existing note about adding explicit non-empty guards to each Producer fixture is a worthwhile robustness follow-up, but the pinned Core extractor tests make it non-gating here.

Verdict: APPROVE
Reasoning: The corpus compares real preview and render outputs through a neutral, independently tested semantic contract, covers the stated drift classes, and all required exact-head checks are green.

— Magi