- Every block now emits a C label (its id) before its code
- generateNextCode emits goto label; for back-edges (visited targets)
- _emitBranch delegates to generateCode (not generateOwnCode), so labels
are emitted consistently in both main and branch traversals
- generateCallWithError threads a shared visited set across all three
emitBranch calls, preventing duplicate label emission for shared blocks
- emitBranch skips roots already visited by previous roots in the same
branch (prevents spurious gotos from shared-block traversal)
- Create codegen/index.js with pure branchDescendants, emitBranch,
generateCallWithError, and generateCFile — zero DOM dependencies
- blocks-proc.js adapters delegate to CodeGen with browser instanceof check
- run.js uses the same CodeGen module instead of duplicating block classes
with their own branchDescendants/emitBranch logic
- Load codegen/index.js in browser before blocks-proc.js
adrien