fix: point GPL corresponding-source URLs at the PCBJam org

Every repo moved from emergence-engineering/ to PCBJam/, but the published
source pointers still named the old org. GitHub's transfer redirect resolves
them (all six checked, 301 -> 200), so nothing is broken today — but it stops
working the moment anyone creates a repo at an old path, and a GPLv3
corresponding-source pointer is a poor thing to leave depending on a redirect.

CI never passes --repo, so the hardcoded default is what actually ships: the
editor's version badge on editor.pcbjam.com has been linking users to the old
org for their source.

Covers the source pointers (licenses.md, terms.md 12.4, REPO_URL and its doc
comment, the three build-script --repo defaults, the site footer's build-commit
link) and the two "our GitHub" org links. Bumps the pcbjam-shared pointer for
the same fix there.

Deliberately untouched: emergence-engineering.com, the company domain behind
contact@ and the EE credit block — the trailing slash in the substitution keeps
it out. And docs/security-audit-glm/, which describes a finding rather than
linking anywhere.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

scripts/deploy/build-editor.mjs

@@ -26,7 +26,7 @@ function parseArgs(argv) {
     tag: null,
     cdn: "https://cdn.pcbjam.com",
     apiBase: null,
-    repo: "https://github.com/emergence-engineering/pcbjam",
+    repo: "https://github.com/PCBJam/pcbjam",
     // Yjs endpoint: defaults to the API origin — board rooms are path-routed
     // (`/parties/board-room/*`) to the sync worker on the same hostname, so the
     // same-site session cookie rides the WS handshake.