feat(web): adopt upstream pull request surfaces

[rynfar]

Adopts upstream's pull request surfaces work (#6039) and the follow-up that scopes its errors per environment (#6490).

Supersedes #13, which GitHub auto-closed when its base branch upstream/2026-08-13-batch was deleted on merge of #12. Same three commits, rebased onto the merged pylon.

What's here

#6039 is upstream's flagship pull request work for this period. It builds on the PR surfaces Pylon already inherited:

• Filters and qualifiers in the list, with an all-server listing so one page reads every connected environment rather than only the primary one
• Update branch action, reactions, and in-place editing of a pull request's title, description, and your own comments, in Markdown with a preview
• A checks popover and smarter diff file ordering
• Provider coverage across GitHub, GitLab, Bitbucket, and Azure DevOps. Azure DevOps accepts a new title and description; its comments stay read-only, as they already were

#6490 then scopes pull request errors to the environment that produced them, which only makes sense once the list spans several.

Pylon adaptations

One commit at the end:

• The one conflict was SidebarChrome.tsx, where Pylon gated the pull requests link on the primary environment's capability and upstream widens it to any connected one. Resolved toward upstream, since all-server listing is the feature.
• Upstream's resolution also added a useLocation subscription to derive which footer page is open. Pylon's footer already derives exactly that from its own pathname/onFooterPage, and upstream only uses the value as a boolean, so I dropped the duplicate rather than run two router subscriptions in the sidebar footer.
• Rebranded Update your T3 Code servers to browse pull requests. to say Pylon, plus the command palette test fixtures.
• Turned four repeatedly-scanned arrays into sets (labels in three filter paths, statuses in the checks reducer). These are scanned once per filter per row, so the list pays for them.

Two react(no-array-index-key) warnings remain in PullRequestChecksPopover.tsx and PullRequestSummaryTab.tsx. Both are deliberate upstream choices with comments explaining them: the host decides how many check runs share a name, so position disambiguates and the index is a suffix on a name-and-url key rather than the key itself. I left that reasoning intact instead of papering over it.

Verification

• vp test run over all 30 touched test files: 887 passed.
• Typecheck on @t3tools/web, t3, @t3tools/contracts, @t3tools/client-runtime: no errors.
• vp check repo-wide: clean apart from the two documented warnings above. Baseline for these files before #6039 was clean, so those two are the only lint delta.

Verified in a real client against a seeded copy of real data, driving the actual GitHub provider:

• All-server listing showing pull requests from three projects across more than one repository
• Filter popover renders every qualifier — State, Involvement, Draft, Review, Checks, Project — and applying Review: Approved narrowed the list to only approved rows and wrote &review=approved into the URL
• Detail panel on a live pingdotgg/t3code pull request showed update branch ("This branch is out-of-date with main by 1 commit"), reactions, and timeline ordering
• In-place editing is correctly permission-gated: Edit title / Edit description appear on the viewer's own authored pull request and are absent on someone else's
• #6490's environment scoping visible as selectedEnvironmentId in the detail URL
• No error alerts on any surface exercised

Model: Claude Opus 5. Harness: Claude Code.

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