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/ui/components/Comments/Comments.scss

@@ -0,0 +1,76 @@
+.comments-section {
+  width: 100%;
+}
+
+.comments-box {
+  max-width: inherit;
+  padding: 0;
+}
+
+.comments-list {
+  list-style: none;
+  padding: 0;
+  margin: 0;
+}
+
+.comment {
+  padding: 0.75em 0;
+  border-bottom: 1px solid rgba(0, 0, 0, 0.08);
+}
+
+.comment-header {
+  display: flex;
+  justify-content: space-between;
+  font-size: 0.9em;
+}
+
+.comment-author {
+  font-weight: bold;
+}
+
+.comment-date {
+  color: #888;
+}
+
+p.comment-content {
+  white-space: pre-line;
+  margin: 0.4em 0;
+}
+
+.comment-media-image {
+  max-width: 100%;
+}
+
+.comment-media-youtube iframe {
+  width: 100%;
+  min-height: 240px;
+  border: 0;
+}
+
+.comment-actions .btn {
+  padding-left: 0;
+  padding-right: 0.75em;
+}
+
+.comment-actions .btn.active {
+  font-weight: bold;
+}
+
+/* keep the previous "remove" button neutral (not danger red) */
+.comment-owner-actions .remove-action {
+  color: rgb(51, 51, 51);
+}
+
+.comment-form .create-comment {
+  height: 9em;
+  margin-bottom: 0.5em;
+}
+
+.comment-login-hint {
+  color: #888;
+  font-style: italic;
+}
+
+.img-avatar {
+  margin-right: 5px;
+}