Cite → open in the Code browser

Goal. Inside kolu’s Code-tab preview, clicking a <Cite> ref jumps to that file at the line in the Code browser tree (with Pierre’s line highlight) — not a GitHub blob in a new tab. Outside kolu (GitHub, a plain browser), it stays an ordinary blob link.

Why defer, not drop — this is wiring, not new infra

Three pieces already exist; the feature just connects them, and <Cite> is the single producer, so it’s a localized change:

• <Cite> centralizes every file:line ref → one component + one host handler.
• Opening a file:line is solved — packages/client/src/right-panel/openInCodeTab.ts:71 exposes openInCodeTab({ ref, repoRoot, targetMode }), which opens a path:line in the Code tab with the line highlighted (already used by terminal-link clicks and the right-click “Open path:N” menu).
• The iframe↔host bridge already exists — packages/artifact-sdk/src/client/bridge.ts:103 (observeIframeNavigation) carries in-iframe events to the host, and packages/solid-browser/src/previewPath.ts:30 (pathFromPreviewPathname, from @kolu/solid-browser) maps a preview URL back to a repo path — that’s how the preview already follows links (packages/client/src/right-panel/BrowseIframeRenderer.tsx:50).

Mechanism — two options

• A — dedicated bridge message (preferred). Add a kolu-artifact-sdk:open-source { path, line } message. <Cite> posts it on click; the host handler calls openInCodeTab. Keeps “open source in the tree” separate from the existing “navigate/swap the previewed file” semantics.
• B — piggyback on navigation. <Cite> links into the file route with #Lnn; reuse observeIframeNavigation + parse the line. Cheaper, but overloads the preview-swap path with a second meaning (needs a discriminator).

Roadmap

• ○ 1Confirm the artifact-sdk is injected into Atlas previews and a <Cite> click can reach the bridge.
• ○ 2Add open-source { path, line } to the artifact-sdk bridge (both ends).
• ○ 3Host handler maps it to openInCodeTab({ ref, repoRoot, targetMode: "browse" }).
• ○ 4<Cite> progressive enhancement — blob href by default; intercept + post when the bridge is present.
• ○ 5Test (analogous to file-ref-link.feature): click a cite in a previewed note → the tree opens the file + line highlight.

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Seedling plan — deferred from the component-kit work. The kit’s <Cite> is what makes this a localized change rather than a cross-cutting one.