🤖 fix: add CoderWorkspaceProxy terms to cspell dictionary

The docs-quality check failed on new CoderWorkspaceProxy resource names.
Add the new singular/plural words to `.cspell.json` so docs CI passes.

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_Generated with [`mux`](https://github.com/coder/mux) • Model: `openai:gpt-5.3-codex` • Thinking: `xhigh` • Cost: `$0.62`_

<!-- mux-attribution: model=openai:gpt-5.3-codex thinking=xhigh costs=0.62 -->

Author: ThomasK33

.cspell.json

@@ -19,6 +19,8 @@
     "codertemplates",
     "coderworkspace",
     "coderworkspaces",
+    "coderworkspaceproxy",
+    "coderworkspaceproxies",
     "coderprovisioner",
     "coderprovisioners",
     "controllerapp",