refactor: extract @hyperframes/studio-server from core

[miguel-heygen]

Summary

Extracts the studio preview server — the studio-api Hono routes, helpers, and server wiring — out of @hyperframes/core/src/studio-api/ into a new @hyperframes/studio-server package.

Part of #1749: pulls the HTTP/preview server out of core so an embedder can mount the studio backend without depending on the entire core surface, and so core stops carrying a web server it doesn't need at render time.

Part 3 of 3 — stacks on #1755 (@hyperframes/parsers). Independent of Part 2 (lint); merge A first, then B and C in either order.

What moves

Source moved out of core (src/studio-api/)	~9,100 LOC removed
New package source	~5,700 LOC
Files in new package	49
Tests carried over	201 passing

This includes the route handlers (files, thumbnail, mutation endpoints), the source-mutation helpers, and the server bootstrap.

Bundle footprint

Artifact	Size
dist/ (unpacked)	592 KB
npm tarball (packed)	124 KB (19 files)

How @hyperframes/core changes

packages/core/src/studio-api/index.ts becomes a @deprecated re-export stub pointing at the new package, so @hyperframes/core/studio-api imports keep resolving.

The notable wrinkle: this creates an intentional circular workspace dependency.

@hyperframes/core  ──(stub re-export)──▶  @hyperframes/studio-server
@hyperframes/studio-server  ──(real usage)──▶  @hyperframes/core

core re-exports studio-server for back-compat, while studio-server genuinely consumes core's types/compiler. tsup handles it by marking both @hyperframes/* packages external during each build, so neither bundles the other — the cycle exists only in the module graph, never in the emitted output. core picks up @hyperframes/studio-server as a dependency; studio-server depends on core + parsers + hono + linkedom + postcss.

Design notes

• The studio routing test (thumbnail.test.ts) moves with the routes from packages/core to packages/studio-server; the preview-regression workflow is updated to point at the new location.
• "bun" export condition before "node" (same convention as the rest of the stack) keeps the dev loop build-free while Node/tsx/Docker resolve built dist/.

Test plan

• bun run --filter @hyperframes/studio-server test — 201 tests pass
• bun run --cwd packages/cli test — 1045 tests pass
• bun run build — full monorepo build succeeds (circular dep resolves cleanly)
• Preview parity + regression shards pass on CI
• Fallow audit passes on CI

[miguel-heygen]

• refactor: extract @hyperframes/studio-server from core #1757 👈 (View in Graphite)
• refactor: extract @hyperframes/parsers from core #1755 : 1 other dependent PR (#1756 )
• main

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[terencecho]

Clean, well-executed extraction. The circular workspace dep is the most interesting risk on paper, but it's structured safely — happy to ship.

Verified

• Circular dep is safe. Both studio-server/tsup.config.ts:14 and core's tsup pipeline rely on tsup's default-externalize-deps-from-package.json behavior (same pattern as sibling parsers/lint). studio-server/package.json:90 declares @hyperframes/core in deps → tsup emits a runtime import rather than bundling. The cycle is deep — core/src/index.ts doesn't import studio-api at top level, and studio-server/src/index.ts doesn't directly import @hyperframes/core at top level either — so ESM lazy module eval breaks it before either side initializes. Bun-dev resolves both to src/... but the same depth saves it.
• Backwards-compat stubs complete. Core's package.json still declares ./studio-api, ./studio-api/screenshot-clip, ./studio-api/manual-edits-render-script, ./studio-api/studio-motion-render-script, ./studio-api/draft-markers, ./studio-api/finite-mutation. Each corresponding packages/core/src/studio-api/helpers/<file>.ts is a 2-line export * from "@hyperframes/studio-server/<sub>" stub. Old imports continue to resolve.
• No silent route drop. packages/studio-server/src/createStudioApi.ts registers 10 routes (projects/storyboard/files/preview/lint/render/thumbnail/waveform/fonts/registry) — identical to master's packages/core/src/studio-api/createStudioApi.ts. Verified line-by-line.
• CLI mount sig preserved. cli/src/server/studioServer.ts:242-258 just swaps the import path (@hyperframes/core/studio-api → @hyperframes/studio-server); the createStudioApi(adapter) call shape is unchanged.
• Test relocation parity. preview-regression.yml:86 correctly updated to bun run --cwd packages/studio-server test -- src/routes/thumbnail.test.ts. Workflow also builds @hyperframes/studio-server before core (line 80). Dockerfile.test:78,93 mirrors this.
• Stack-base: gh pr diff 1757 is the studio-server delta only — no parser-package leakage.
• Dependency hygiene: studio-server/package.json:90-96 has core + parsers + hono + linkedom + postcss + postcss-selector-parser. Core picks up @hyperframes/studio-server at packages/core/package.json:357. CLI / producer / studio all updated. set-version.ts:25 + publish.yml:128 add studio-server to the version-sync + publish order (parsers → studio-server → core) — correct given the cycle.

Non-blocking polish

• Stale consumer imports on the deprecated path. cli/src/utils/staticProjectServer.ts:4, cli/src/commands/play.ts:110, studio/src/hooks/gsapScriptCommitHelpers.ts:1, studio/src/hooks/useDomEditCommits.ts, studio/src/hooks/useGsapScriptCommits.ts, studio/src/hooks/useGestureRecording.ts, cli/src/commands/present.ts all still import from @hyperframes/core/studio-api/*. These resolve via the stubs and work, but a bulk-migrate (either in this PR or as a follow-up issue) would lock in the new package name and let the stubs be deleted in a future round.
• Build-order asymmetry. Workflow builds studio-server before core even though core depends on studio-server. tsup's dts generation resolves types via "types": "./src/index.ts" so it works — but a one-line comment in the workflow noting why this order is correct (it's not topological — the "types" condition rescues it) would help the next person who touches it.

— Review by tai (pr-review)

The base branch was changed.