fix(post-suspension): migrate github.com/Molecule-AI refs to git.moleculesai.app (Class G #168)

The GitHub org Molecule-AI was suspended on 2026-05-06; canonical SCM
is now Gitea at https://git.moleculesai.app/molecule-ai/. Stale
github.com/Molecule-AI/... URLs return 404 and break tooling that
clones / pip-installs / curls them.

This bundles all non-Go-module URL fixes for this repo into a single PR.
Go module path references (in *.go, go.mod, go.sum) are out of scope
here -- tracked separately under Task #140.

Token-auth clone URLs also flip ${GITHUB_TOKEN} -> ${GITEA_TOKEN} since
the GitHub token does not auth against Gitea.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

README.md

@@ -115,5 +115,5 @@ shared and platform-managed, not in plugin scope).
 - internal `product/plugin-architecture-v2.md` — target arch for v2
   migration
 
-[molecule-core#1957]: https://github.com/Molecule-AI/molecule-core/issues/1957
+[molecule-core#1957]: https://git.moleculesai.app/molecule-ai/molecule-core/issues/1957
 [plugin-architecture-v2]: https://git.moleculesai.app/molecule-ai/internal/src/branch/main/product/plugin-architecture-v2.md

known-issues.md

@@ -32,7 +32,7 @@ axis. At that point:
 - Grade-A hot reload becomes possible (platform can re-emit the file
   without a workspace restart).
 
-[v2]: https://github.com/Molecule-AI/internal/blob/main/product/plugin-architecture-v2.md
+[v2]: https://git.moleculesai.app/molecule-ai/internal/blob/main/product/plugin-architecture-v2.md
 
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