escala 2+3: Meteor 1.8.3 -> 2.3 (Mongo 3.2 compatible), dead-package remediation

Reaches Meteor 2.3 building + running against Mongo 3.2, REST smoke test
byte-identical to the 1.6.1.1 baseline (all 12 Flutter endpoints green).

Dead/abandoned Atmosphere packages removed or replaced (the upgrade blockers):
- arkham:comments-ui (no Meteor 2.x build; pinned accounts-password@1.x):
  reimplemented the fire-page comments as a React feature:
    imports/api/Comments/ (collection, server methods, publication, media
    analyzers, new-fire-comment email) + imports/ui/components/Comments/CommentsBox.
    Comment text now rendered as safe plain text + image/youtube embed (was
    markdown-to-HTML). Wired into Fires.js; sitemaps.js + migration v11 updated
    to the new collection. Old Blaze/startup comments files deleted.
- nimble:restivus (REST API; pinned accounts-password@1.3.3, CoffeeScript source
  that crashes this build host): vendored as a local package
  packages/nimble-restivus with the .coffee precompiled to plain JS and the
  accounts-password constraint loosened to 2.x. REST behavior unchanged
  (verified by smoke test). This also dropped the entire iron:router stack.
- maximum:server-transform (+ peerlibrary:*, meteorhacks:zones/inject-initial):
  unused; removal broke Meteor.publishTransformed in FalsePositives publications
  -> replaced with plain Meteor.publish (no transform was configured).
- less, markdown (no source files), and the dead test stack
  (meteortesting:mocha, practicalmeteor:chai, xolvio:cleaner) which transitively
  pulled coffeescript@1.0.17 — the build plugin that crashed meteor-tool
  (node_contextify assertion) on this machine. Removing it unblocked the build.
- fourseven:scss 4.5.4 -> 4.14.1 (node-sass 4.5.3 doesn't build on node 12).

npm-mongo driver at 2.3 is 3.9.x — still compatible with the production Mongo
3.2 replica set.

imports/api/Comments/Comments.js

@@ -0,0 +1,29 @@
+/* eslint-disable import/no-absolute-path */
+import { Mongo } from 'meteor/mongo';
+
+/*
+ * Comments collection (fire-page comments).
+ *
+ * Replaces the abandoned `arkham:comments-ui` Atmosphere package (no Meteor 2.x
+ * build) with a small React + methods implementation. The collection name
+ * ('comments') and the core document shape are kept so existing production
+ * documents keep rendering:
+ *
+ *   { referenceId: 'fire-<id>', content, userId, username,
+ *     media: { type, content }, likes: [userId], dislikes: [userId],
+ *     status: 'approved', createdAt, updatedAt }
+ *
+ * Legacy documents may also carry replies[]/starRatings[]/ratingScore/
+ * isAnonymous — those features were disabled in this app's config and are
+ * ignored by the new UI.
+ */
+const Comments = new Mongo.Collection('comments');
+
+// Writes only through the vetted server methods.
+Comments.deny({
+  insert: () => true,
+  update: () => true,
+  remove: () => true
+});
+
+export default Comments;