style(docsync): drop dash punctuation from the added comments and test titles

The lines this branch adds used em and en dashes as sentence
punctuation across comments, JSDoc, CSS comments and test titles. Each
one is rewritten with a comma, a colon, parentheses or a second
sentence, keeping what the sentence said.

Only lines this branch adds are touched; everything that already
exists on dev stays as it is. No logic, error code or logged message
changes. The only string literals affected are describe and it titles,
which now read "X: topic" like the rest of the provider tests.

client/src/api/client.ts

@@ -1361,7 +1361,7 @@ export const filesApi = {
 /**
  * Document sync: one provider connection per trip, shared by every member.
  *
- * Trip-scoped rather than user-scoped on purpose — a per-user connection would
+ * Trip-scoped rather than user-scoped on purpose: a per-user connection would
  * make a document's visibility depend on whose credentials fetched it, which is
  * the opposite of what a shared trip needs.
  */

client/src/api/wsEventPolicy.ts

@@ -81,7 +81,7 @@ export const HANDLED_OUTSIDE_TRIP_STORE = [
   // who has the book open, and where their pointers are)
   'journey:book:peers',
   'journey:book:cursor',
-  // Document sync — components/Files/docsync/useDocSync re-reads the bindings
+  // Document sync: components/Files/docsync/useDocSync re-reads the bindings
   // and their counts. Content-free like the bag ping: what a run changed is
   // per-binding server state, and the files it moved arrive as file:* events.
   'docsync:changed',