ServerWorkerd.create builds the fetch handler for a Durable Object's fetch(),
with every intentionally-local service replaced: the database runs on the
injected DO SQLite, plugin discovery is precompiled-only, MCP is remote-only,
Snapshot and Vcs degrade to empty results, and Shell/FileSystem/Pty fail with
a clear defect until a remote sandbox backs them.
Threading it through needs one seam: createRoutes and ServerFetch.make take
runtime-profile replacements applied after the standard set, so later entries
win. script/workerd-probe.ts pins that the graph bundles under the workerd
condition without bun builtins.
Kit Langton
2913aee8ba