prompt(agents): make the copyeditor exhaustive in one pass (#315)

The copyeditor had to be re-run several times to surface all issues: it has no
'work the whole document' instruction (unlike the developmental editor and the
narrator), and the severity labels nudge it toward reporting only the salient
few.

- Add a HOW TO WORK section (ru + en): one pass over the whole text start to
  finish; flag EVERY violation including all repeat occurrences and [Minor]
  items; don't summarize instead of marking up; one run covers the whole text,
  not just 'the most important'.
- proofreader version 5 -> 6, content-hash lock refreshed.

Check: agent-roles-catalog check.mjs OK.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

agent-roles-catalog/scripts/content-hashes.json

@@ -12,8 +12,8 @@
     "hash": "66fe653003b4f63ef3c3a5c5c48552fe47daeefffc16907c37c35f0e8da98851"
   },
   "proofreader": {
-    "version": 5,
-    "hash": "40af08c51e03c24b1986ac5cd679434e023afe31a819748966ccb0c6c62f0401"
+    "version": 6,
+    "hash": "a2895a5695a5136c736f8849985c078bb837679ec61483b00a4ca3a5e934324d"
   },
   "researcher": {
     "version": 1,