Web client comments describe the code to a stranger (#6222)

Milestone 546 "Bring the repo to the comment standard (rule 32) and
compose defaults (rule 198)", step #6222 "Comment standard sweep: web
client (frontend/)".

Comments, docstrings and template notes across frontend/ now say what
the code does and the non-obvious why as present-tense facts. Issue,
task, note, milestone and family-idea references are gone, along with
narration of what used to happen: the titles index's wiki-link origin
and its once-per-session load (#5165), the card-controls overlap a
phone showed (task 2697), the M7 and M10.9 labels, and the card
unification behind the reminders lens (task 1913). Hazards stay as
facts, among them LEAVE_MS matching the editor's leave duration, the
Android client twin that must not be widened, and keeping leavers in
flow in the multi-column masonry.

62 files, comments only: a comment-stripping diff of every changed file
against HEAD is identical.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/src/views/BoardView.vue

@@ -129,7 +129,7 @@ function onBoardKey(e: KeyboardEvent) {
     e.preventDefault();
     openEditor(note);
   } else if (key === "x" && !inTrash.value && isOwnNote(note)) {
-    // Trash is the owner's; archive and pin below are everyone's own (#5176).
+    // Trash is the owner's; archive and pin below are everyone's own.
     e.preventDefault();
     void notes.trash(note.id);
   } else if (key === "e" && !inTrash.value) {
@@ -295,9 +295,9 @@ const gridBinds = computed(() => ({
 </script>
 
 <template>
-  <!-- `pb-[…safe-area-inset-bottom]`: the board is the last thing on the page, so
-       it is what ends up underneath the gesture bar once `viewport-fit=cover` lets
-       the page draw there. Added to the existing py-6 rather than replacing it. -->
+  <!-- `pb-[…safe-area-inset-bottom]` on top of py-6: the board is the last thing on
+       the page, so it is what sits under the gesture bar once `viewport-fit=cover`
+       lets the page draw there. -->
   <div class="mx-auto w-full max-w-6xl px-4 pb-[calc(1.5rem+env(safe-area-inset-bottom,0px))] pt-6">
     <button
       v-if="isMainBoard"