Allow fetch in db library vm contexts

Db library scripts are basically a JS module scoped to the db, and
handlers already get fetch — but runLibrary's own vm context only
bound sql/console, so any library calling fetch (e.g. the chat db's
OpenAI call) threw ReferenceError. Since library calls are often
fire-and-forget inside setTimeout (no rejection handler), that
crashed the whole process. Bind fetch in all three places a library
script runs: request-time (runLibrary), the library-editor save eval,
and repl.

Also add `bliss link` to bliss-cli for jumping straight to a
structure/route/template/db's workshop editor URL, including
resolving a db by its require('db')(alias) name.

CLAUDE.md

@@ -32,7 +32,7 @@ The Express app has two kinds of routes:
 
 User route handlers run in `vm.createContext()` with a restricted API:
 - `require('eta')` — Eta template instance scoped to the structure
-- `require('db')` — getter for named database instances. `require('db')(alias)` returns `{ library, sql }`: `sql` is the raw `better-sqlite3` instance for that db, and `library` is `module.exports` from that db's own "library" script (arbitrary JS, edited via `/workshop/:structure_id/db/:db_id/library`, run once per request with `sql` bound in its own vm context — see `bootstrapContext` in `index.js`). Handlers typically call helper functions off `library` rather than writing raw SQL inline.
+- `require('db')` — getter for named database instances. `require('db')(alias)` returns `{ library, sql }`: `sql` is the raw `better-sqlite3` instance for that db, and `library` is `module.exports` from that db's own "library" script (arbitrary JS, edited via `/workshop/:structure_id/db/:db_id/library`, run once per request with `sql`, `console`, and `fetch` bound in its own vm context — see `runLibrary` in `index.js`). Handlers typically call helper functions off `library` rather than writing raw SQL inline.
 - `require('push')` — web-push library
 - `require('files')` — `{ saveFile }` helper
 - `console.log` — writes to the app's `logs` table (not stdout)