fix(webapp): a wikilink is a real link, not a wiki: string (BEA-136)

[ssowonny]

TL;DR

• Copy-link, middle-click and open-in-new-tab on a [[wikilink]] handed you wiki:guide — a dead string. Plain clicks always worked, which is why nobody caught it.
• The anchor now carries the real /<project-id>/guide.md URL, so every way of using a link works the way it looks like it should.
• A wikilink pointing at nothing loses its href and renders greyed with a dotted underline, instead of pretending to be a link.
• Free fix while the line was open: cmd-clicking a plain relative markdown link now opens a tab too, instead of hijacking the current one.
• Known gap, deliberate: /s/<token> share pages still render dead wikilinks — the target isn't part of the share, so a real URL would hand an anonymous visitor a 404.

---

Wikilinks resolved at click time. The DOM kept the server's wiki: marker, and the click handler rescued only the one path that never reads the attribute:

flowchart TD
    A["one rendered anchor<br/>&lt;a href=&quot;wiki:guide&quot;&gt;"] --> B["left-click"]
    A --> C["copy link / middle-click / cmd-click / new tab"]
    B --> D["handler intercepts,<br/>opens guide.md<br/>WORKS"]
    C --> E["browser follows href<br/>wiki:guide<br/>DEAD"]

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The fix moves the match one step earlier, into transformHTML — the pass that already rewrites this HTML before the mount (relative image srcs, external-link targets). Nothing patches the mounted dangerouslySetInnerHTML subtree, which is the failure CLAUDE.md calls out by name.

flowchart LR
    S["server<br/>markdown.go<br/>href=wiki:guide"] --> T["transformHTML NEW<br/>match flatFiles<br/>href=/&lt;pid&gt;/guide.md"]
    T --> D["mounted DOM<br/>copy, middle-click,<br/>new tab all real"]
    D --> H["click handler<br/>plain -&gt; openFile<br/>modified -&gt; browser"]

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What changed

Where	Change
src/util.ts	New pure resolveWiki(target, files) — the matching rules lifted verbatim out of openWikilink (exact path, path + .md, basename, basename + .md, all case-insensitive, path before basename). Pure and DOM-free, so node --test covers the whole matrix without a browser.
src/components/FileView.tsx	transformHTML gains files + projectId. A hit gets href=urlForPath(hit.path, projectId) and a data-wiki marker; a miss loses its href and gets class="wiki-missing" + a title. openWikilink is gone.
src/components/FileView.tsx	handleLinkClick intercepts data-wiki anchors only, and returns early for modified / non-primary clicks — the same rule nav.ts:linkProps applies to every other link in the app.
src/apps/Browser.tsx	Passes projectId={project?.id} down. Volume mode has none, so urlForPath yields /<path> there.
src/style.css	.markdown a.wiki-missing — an anchor with no href loses link styling entirely, and a broken cross-reference silently reading as prose is worse than the dead URL it replaced.
e2e_serve_test.go	The seeded index.md gains a dangling [[nowhere]], so the unresolved case has something to assert against. Content-only change to an existing op.

markdown.go is untouched. wiki: stays the marker the server leaves behind (RenderMarkdown is pure and has no file tree) — it just never survives to the mounted DOM.

Why data-wiki rather than "any root-absolute href": an author writing [x](/somewhere) in their own markdown keeps today's behavior instead of quietly becoming an SPA route, and the target path is read back directly instead of re-parsed out of a URL.

The one deviation from the reviewed plan

resolveWiki takes a structural { path, name }[] instead of importing Node from api/types. Same call sites, same behavior, one less import in the module the node test runner loads.

Before / after

The bug lives in the href attribute, so the screenshots only show the visible half — the new unresolved-wikilink treatment. The attribute itself is in the DOM read below them.

before (origin/main)	after

The same page's anchors, read out of the live DOM:

before:  [ {text: "guide",   href: "wiki:guide"},
           {text: "notes",   href: "notes/readme.md"} ]

after:   [ {text: "guide",   href: "/<pid>/guide.md"},
           {text: "notes",   href: "notes/readme.md"},
           {text: "nowhere", href: null, class: "wiki-missing"} ]

Verification

• go test ./... — pass (full suite).
• npm test — 79 pass, including the new resolveWiki matrix (path/basename precedence, implied .md, mixed case, miss returns undefined).
• npm run e2e — 171 pass, 1 skipped (pre-existing). The existing wikilink navigates to the target file now asserts getAttribute("href") and that a plain click did not reload the document; a new spec covers the modified click staying put and [[nowhere]] rendering with no href and no wiki: anywhere in #content.
• npm run build run and internal/webapp/static/ committed; check-dist.sh clean.
• UI checked by driving the real hub (screenshots above are that session).

The architecture/webapp-frontend.md note on transformHTML gained a sentence describing the new pass. No types or relationships changed, so there's no architecture diff section.

Build session

cd $(git worktree list | grep bea-136 | awk '{print $1}') && claude --resume 283443ee-89d8-4f4e-9de0-67a725084139

(Only works on the machine that built this.)