refactor: make @hyperframes/lint depend only on parsers (#1773)

* refactor: make @hyperframes/lint depend only on parsers, not core

Relocates the leaf utilities lint pulled from core — URL/asset-path helpers,
font aliases, and the slideshow manifest parser — into the standalone
@hyperframes/parsers base, and drops @hyperframes/core from lint's
dependencies. Core keeps back-compat re-export stubs at the old paths, so
producer/studio/cli are unchanged.

Why: lint was the lightweight validator from #1749, but depending on core
transitively pulled studio-server (hono) and bpm-detective — irrelevant to
linting. Now installing @hyperframes/lint pulls only parsers + postcss, and
the core<->lint dependency cycle is gone.

- parsers main entry stays browser-safe (pure utils only); the node:path
  asset helpers live behind the new @hyperframes/parsers/asset-paths subpath
- slideshow parser exposed via @hyperframes/parsers/slideshow

* feat(lint): add browser entry; harden CSS url() regex (ReDoS)

@hyperframes/lint/browser — a fully client-side rule engine (lintHyperframeHtml,
lintMediaUrls, shouldBlockRender) with zero node: builtins, so browser-only
editors can validate compositions with no Node.js and no server round-trip.
Closes the browser-validation ask on #1749.

- shouldBlockRender extracted from the fs-bound project.ts into its own pure
  module so the browser entry stays node-free
- pure composition primitives (data types, font aliases, URL helper) exposed via
  a new recast-free @hyperframes/parsers/composition subpath, so the browser
  bundle tree-shakes out the GSAP/recast machinery (verified: esbuild
  platform=browser bundles with 0 node builtins)
- lint built with a platform:browser tsup pass — compile-time guarantee the
  browser entry never pulls a node builtin
- harden CSS_URL_RE against polynomial ReDoS (CodeQL js/polynomial-redos);
  behavior-preserving, verified against existing tests + an old/new parity check
- parsers/lint marked sideEffects:false

packages/core/src/utils/urlPath.ts

@@ -1,11 +1,2 @@
-export function decodeUrlPathVariants(path: string): string[] {
-  const variants = [path];
-  try {
-    const decoded = decodeURIComponent(path);
-    if (decoded !== path) variants.unshift(decoded);
-  } catch {
-    // Malformed percent sequences may be literal filesystem names.
-  }
-
-  return variants;
-}
+// Moved to @hyperframes/parsers. Re-exported here for back-compat.
+export { decodeUrlPathVariants } from "@hyperframes/parsers";