📖🔧：drop bundler and the stale dev port

This doc predates the move off Jekyll: it still told readers to
`bundle install` a Gemfile that no longer exists, and pointed them
at Jekyll's default port, 4000, instead of the 3000 that eleventy's
dev server actually serves on.

Signed-off-by: Derek Lewis <DerekNonGeneric@inf.is>
Assisted-by: Claude-Code:claude-sonnet-5

Author: DerekNonGeneric

collections/_docs/README.md

@@ -25,13 +25,6 @@ command from the project workspace root (if necessary):
 pnpm install
 ```
 
-```console
-# Configure Bundler setting local gem install path to avoid permission errors.
-bundle config set --local path vendor/bundle
-# Install the dependencies specified in the Gemfile.
-bundle install
-```
-
 <br /><br />
 
 ### Running Locally
@@ -47,7 +40,7 @@ nps start
 ```
 
 Once the script finishes building the documentation site, one may visit it at
-<http://localhost:4000>.
+<http://localhost:3000>.
 
 <br /><br />