docs: write the pages in neutral third person

The docs pages carried 36 attributed opinions — "Matt's own answer",
"his position is", quoted replies from the author. A page is a
technical document about a skill, so the substance of each finding
stays and the attribution goes: "the fix is a direct instruction: …",
"the split comes down to session count".

Quotes from *users* stay, anonymous as they already were — those are
evidence about the skill in the wild rather than the author's view.

Records the rule in .agents/writing-docs.md so new pages don't
reintroduce it.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

docs/engineering/wizard.md

@@ -56,7 +56,7 @@ The agent that writes a wizard never runs it end to end, because it opens browse
 
 **Do my API keys end up in the model's context?**
 
-No. The agent writes a script; it doesn't run it. You run the script yourself, and it captures the key with hidden terminal entry and writes it straight to `.env` or `gh secret`. Matt's answer to this on launch day was "No, because it's a CLI — the LLM is not connected to it." One caveat: that holds for values the wizard captures at runtime. If you paste a key into the chat while scoping the procedure, it's in the [context](https://www.aihero.dev/ai-coding-dictionary/context) like any other pasted text.
+No. The agent writes a script; it doesn't run it. You run the script yourself, and it captures the key with hidden terminal entry and writes it straight to `.env` or `gh secret`. The wizard is a CLI, and the model is not connected to it. One caveat: that holds for values the wizard captures at runtime. If you paste a key into the chat while scoping the procedure, it's in the [context](https://www.aihero.dev/ai-coding-dictionary/context) like any other pasted text.
 
 **Can I go back and fix a value I mistyped?**