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/research.md

@@ -38,7 +38,7 @@ The opposite failure exists as well: if your own global instructions forbid an a
 
 **Where should the file live — and should I commit it?**
 
-The skill puts the file where the repo already keeps notes and does not have an opinion beyond that. The community one is fairly settled: ADRs are kept, research files are not. The sharpest version of it, from a Discord thread on exactly this question: "ADRs yes. Everything else archive or delete after done. It otherwise becomes cruft of work and can poison future repo reads if you've drifted away from the spec/research." A research file records what was true on the day it was written, so a stale one is worse than none. Matt's own position is that these artifacts don't really belong in git, and there is no ruling from him on a canonical home — people use Obsidian, a separate knowledge repo, or the issue tracker instead.
+The skill puts the file where the repo already keeps notes and does not have an opinion beyond that. The community one is fairly settled: ADRs are kept, research files are not. The sharpest version of it, from a Discord thread on exactly this question: "ADRs yes. Everything else archive or delete after done. It otherwise becomes cruft of work and can poison future repo reads if you've drifted away from the spec/research." A research file records what was true on the day it was written, so a stale one is worse than none. On balance these artifacts don't really belong in git, and there is no canonical home for them — people use Obsidian, a separate knowledge repo, or the issue tracker instead.
 
 **What counts as a "high-trust" primary source, and who decides?**
 
@@ -50,7 +50,7 @@ No. Nothing auto-loads a past research file; it is a document sitting in the rep
 
 **Why not just ask the agent to go read the docs?**
 
-You can, and Matt did for a long time — his hesitation before shipping this was "I tend to just say that verbatim." Two things the skill buys over the prompt: it runs in the background so your session keeps its [context](https://www.aihero.dev/ai-coding-dictionary/context) clean, and the primary-source constraint and the cited-file output come out the same way every time rather than however you happened to phrase it. Against a [harness](https://www.aihero.dev/ai-coding-dictionary/harness)'s own deep-research mode, the difference is the artifact and the source discipline, not the search. If a two-line prompt gets you what you need on a small question, use the two-line prompt.
+You can, and a two-line prompt saying exactly that was the practice this skill replaced. Two things the skill buys over the prompt: it runs in the background so your session keeps its [context](https://www.aihero.dev/ai-coding-dictionary/context) clean, and the primary-source constraint and the cited-file output come out the same way every time rather than however you happened to phrase it. Against a [harness](https://www.aihero.dev/ai-coding-dictionary/harness)'s own deep-research mode, the difference is the artifact and the source discipline, not the search. If a two-line prompt gets you what you need on a small question, use the two-line prompt.
 
 **When does it stop reading?**