Tell contributors to search open PRs before writing a fix

[rdoupe]

Problem

contributing.md is the doc that governs submitting a fix upstream, and it ships in the omarchy skill — so it is what an agent on a user's machine reads before contributing. It covers forking, style, atomic commits, and running the tests, but says nothing about checking whether the fix already exists.

The backlog is large enough that the omission is expensive. Two clusters found without looking hard:

Lock screen losing password focus after suspend — four open PRs:

PR	Approach
#7164	refocus when secure becomes true
#7592	100ms polling Timer while unfocused
#8560	onActiveFocusChanged reclaims focus
#8869	100ms polling Timer + focus: true

Wi-Fi password reveal toggle — two open PRs: #7815 and #8019 add the same toggle.

I hit that lock bug, diagnosed it, wrote a fix and opened #9089 — the fifth PR on it — before finding the other four. I have closed it as a duplicate. Four people each spent real effort on the same twenty lines, and a maintainer now has to read and compare all of them. This is the fix for what actually went wrong.

Change

Adds four sentences and two gh invocations to the existing ## Submitting a PR section: search before writing, search twice because one query will not catch a PR that words the same area differently, and when an open PR already covers the change, add to it — confirm the bug on your hardware, review the approach, contribute a missing test — instead of opening a competing one.

Docs only, no code or test changes. Hard-wrapped at 78 columns to match the rest of the file.

Opened against contributing.md rather than AGENTS.md because the duplicate gets written before anyone opens the checkout.

[rdoupe]

Closing as a duplicate of #8609, and overlapping #6959.

Both predate this and both are more complete. #8609 adds a "Check It Isn't Already Known" section to this same file covering issues and PRs via gh search, plus default-branch verification. #6959 goes further and makes it a required checkbox in the bug template. This PR only covered PRs, and only in the ## Submitting a PR section — a strict subset.

Worth recording for whoever triages #8609 and #6959, since it is direct evidence they are needed: I opened this without searching first, which is precisely the failure it describes. The same session also produced #9089, a fifth duplicate fix for the lock screen password-focus bug that already had four open PRs (#7164, #7592, #8560, #8869). Both are now closed.

If either #8609 or #6959 needs a concrete example in its rationale, this thread is one.