chore: extend [SYSTEM:→[IMPORTANT: rename + AUTHOR_MAP

Follow-up to #6616 covering the remaining user-injected prompt markers that
the original PR did not touch (reporter's second comment on #6576 explicitly
flagged these). Azure OpenAI Default/DefaultV2 content filters treat any
bracketed [SYSTEM: ...] as prompt-injection and reject with HTTP 400.

Remaining call sites renamed:
- cli.py: background-process notifications (watch_disabled, watch_match,
  completion), MCP reload notice (4 live + 1 docstring)
- gateway/run.py: same notification paths + auto-loaded skill banner +
  MCP reload notice (5 live + 1 docstring)
- tools/process_registry.py: comment reference

Not renamed:
- environments/hermes_base_env.py '[SYSTEM]\n{content}' — RL training
  trajectory rendering only, never sent to Azure, part of a symmetric
  [USER]/[ASSISTANT]/[TOOL] scheme.

AUTHOR_MAP: buraysandro9@gmail.com -> ygd58.

tools/process_registry.py

@@ -776,7 +776,7 @@ class ProcessRegistry:
 
         # Only enqueue completion notification on the FIRST move.  Without
         # this guard, kill_process() and the reader thread can both call
-        # _move_to_finished(), producing duplicate [SYSTEM: ...] messages.
+        # _move_to_finished(), producing duplicate [IMPORTANT: ...] messages.
         if was_running and session.notify_on_complete:
             from tools.ansi_strip import strip_ansi
             output_tail = strip_ansi(session.output_buffer[-2000:]) if session.output_buffer else ""