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>

runbooks/known-failure-modes.md

@@ -123,7 +123,7 @@ remote: error: pre-receive hook declined
 **Cause:** Either (a) branch protection requires PR review, or (b) CI failed on the latest commit.
 
 **Fix:**
-1. Check CI status at: `https://github.com/Molecule-AI/molecule-ai-plugin-ecc/actions`
+1. Check CI status at: `https://git.moleculesai.app/molecule-ai/molecule-ai-plugin-ecc/actions`
 2. If CI failed, fix the failures and push again
 3. If CI passed but push still blocked, use a PR instead of pushing directly to `main`
 

runbooks/local-dev-setup.md

@@ -153,7 +153,7 @@ Verify `plugins_registry` is installed in the active venv:
 ```bash
 pip show plugins_registry
 # If not installed:
-pip install git+https://github.com/Molecule-AI/plugins_registry.git
+pip install git+https://git.moleculesai.app/molecule-ai/plugins_registry.git
 ```
 
 ### CI failure on markdownlint

runbooks/release-procedure.md

@@ -105,7 +105,7 @@ EOF
 ```
 
 Or via the GitHub web UI:
-1. Go to https://github.com/Molecule-AI/molecule-ai-plugin-ecc/releases/new
+1. Go to https://git.moleculesai.app/molecule-ai/molecule-ai-plugin-ecc/releases/new
 2. Select the tag `vX.Y.Z`
 3. Paste the changelog into the release body
 4. Publish release