fix(vscode): claim a free display name and fix the Marketplace README links

[FelixTJDietrich]

Third server-side rejection, third distinct rule:

Verify the Marketplace PAT can write this publisher  ✅
Publishing 'aet-tum.apollon-extension v5.1.1'...
ERROR This extension display name is taken. Please try a different one.

Rather than fix it and find out about rule #4 next run, I put three principal engineers on it — one researching the Marketplace's documented validation surface, one auditing the artifact vsce actually produces, one red-teaming the result.

The blocker

The Marketplace reserves displayName across all publishers, exactly as it reserves name:

"The display name must be unique to the Marketplace."
— Extension Manifest reference

The rule went live 2023-02-01 (vscode-discussions#433) — which is why 29 duplicate display names I sampled from the gallery are all pre-2023 grandfathering.

Apollon is held by the abandoned tumaet.apollon-vscode. Apollon - TUM is the display name our aet-tum.apollon-extension listing already carries, so the update keeps it, and it matches its sibling aet-tum.iris-thaumantias → Artemis - TUM.

The defect nobody would have reported

While auditing the listing, both relative links in the Marketplace README were found to 404 silently. vsce rewrites relative README links against the repository root and ignores repository.directory (vscode-vsce#980, open), so an extension in a subdirectory ships links one level too high — with zero warnings at package time.

Measured with curl against the URLs inside the actual VSIX:

README source	Shipped as
[README.dev.md](./README.dev.md)	.../blob/HEAD/README.dev.md	404
[LICENSE](../LICENSE)	.../blob/HEAD/../LICENSE	404

--baseContentUrl fixes the first. It cannot fix the second: vsce keeps ../ verbatim and GitHub does not normalize .. in a blob path, so it stays broken even with a correct base. That link now points at ./LICENSE.txt, which exists in the extension root and already ships inside the VSIX.

The base URLs are declared once, in package:vsix, and the release workflow packages through that script instead of calling vsce itself — the same duplication that produced the wrong extension ID two PRs ago.

Also corrected

The README advertised SFC; the shipped label is Sequential function chart. All 13 diagram types now match src/shared/diagramTypes.ts exactly.

Verified against the artifact that will actually be uploaded

Not the source tree — the VSIX:

id	aet-tum.apollon-extension
displayName	Apollon - TUM
version	5.1.1 (listing is at 1.0.0)
icon	media/icon.png, present, 256×256 PNG (the live listing currently has no icon asset at all)
LICENSE.txt	present → no interactive vsce license prompt to hang CI
src/, sourcemaps	0 files
every URL in packaged readme.md	200

The one non-200 is npmjs.com → 403, which is Cloudflare bot mitigation against curl; registry.npmjs.org returns 200 for the package.

I also executed the changed CI packaging path locally rather than reasoning about it: installed vsce into a temp prefix, put it on PATH, and ran pnpm run package:vsix from vscode-extension/ — packages cleanly, glob matches exactly one VSIX.

Red team confirmed via vsce v3.9.1 src/publish.ts that --packagePath reads the manifest from inside the VSIX, never from disk — which is what makes the publish job's .nvmrc-only sparse checkout safe, and means the base-URL flags can't disagree with what ships.

lint, typecheck, format:check clean; 44/44 tests pass.

Shipping

Merging is still inert — version is unchanged, so #808's push guard correctly skips. Publish with Actions → Release VS Code Extension → Run workflow on main, dry_run: false.

Residual risk, stated honestly

vsce package performs only local validation; name / displayName uniqueness is enforced only at the server on publish, and there is no documented dry-run. Every rule I could find a trusted source for is now satisfied, and the two identity fields are values this listing already holds — the strongest guarantee available short of publishing. Unverified by any trusted source: whether a reserved-name list exists, and any description length cap.

Unrelated and still open: OVSX_PAT unset (Open VSX skipped by design), and the vscode-marketplace environment has no protection rules.

🤖 Generated with Claude Code

[Claudia-Anthropica]

@FelixTJDietrich Looks good. The Marketplace identity and README link handling are consistent, and the checks are green.