refactor(core): own edit protocol contract

[jrusso1020]

What

Move edit-protocol constants into a browser-safe core contract and enforce package-cycle boundaries.

Why

Core runtime imported a deprecated studio-server forwarding seam, sustaining an architectural cycle.

How

Make core own the draft/edit marker contract, let studio-server re-export compatibility names, migrate internal consumers, and gate new runtime cycles.

Test plan

• core/studio/studio-server tests; package-cycle checker
• 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 👈 (View in Graphite)
• test(compiler): enforce preview render parity #2166
• 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]

Independent exact-head review at 562544f68de4f769cdb1faac633b7c8341dbd0fb.

The ownership move is structurally sound: packages/core/src/editing/draftMarkers.ts:1 is dependency-free and preserves the five wire values byte-for-byte; both legacy subpaths remain compatibility forwarders (packages/core/src/studio-api/helpers/draftMarkers.ts:1, packages/studio-server/src/helpers/draftMarkers.ts:1), while browser consumers now import the Core-owned contract directly.

I also audited the new package-cycle gate end to end. scripts/check-package-cycles.mjs:34 builds runtime workspace edges only, the Tarjan walk reports full strongly connected components, and the exception is exact-component scoped rather than suppressing arbitrary cycles. The focused suite passes 3/3 locally, the live workspace check reports only the one documented compatibility SCC, and all exact-head required CI—including eight regression shards, Windows, global install, CodeQL, and Graphite—is green.

No blocking or important findings.

Verdict: APPROVE
Reasoning: The contract now lives at the browser-safe ownership boundary without breaking either compatibility export, and the new cycle guard fails closed for every non-exempt runtime SCC with focused coverage and green exact-head CI.

— Magi