fix(stream-retry): collapse two-line drop status, name provider, and let agent.log capture diagnostics (#22993)

Subagent stream drops were spamming the parent terminal with two lines
per blip ('Connection dropped...' + 'Reconnected...') while leaving zero
breadcrumb in agent.log to debug them.

Two underlying bugs, fixed together:

1. quiet_mode raised the run_agent/tools/etc. loggers to ERROR, which
   filters records before root-logger file handlers see them. The comment
   claimed 'File handlers still capture everything' — that was wrong.
   Removed in both run_agent.py and cli.py; console quietness already
   comes from hermes_logging not installing a console StreamHandler in
   non-verbose mode.

2. The stream-retry blocks emitted two _emit_status calls per drop
   ('⚠️ Connection dropped... Reconnecting...' + '🔄 Reconnected —
   resuming…') with no provider name, so multi-provider sessions had to
   dig through agent.log to attribute a drop. Replaced both call sites
   with a single _emit_stream_drop helper that emits ONE line naming the
   provider and error class, and always writes a structured WARNING to
   agent.log with subagent_id, depth, provider, base_url, error_type.

Net UX change: 6 lines per triple-subagent drop → 3 lines, each
naming the provider. agent.log now has a structured breadcrumb per
retry that didn't exist before.

Tests: 6 new tests in tests/run_agent/test_stream_drop_logging.py
covering the logger-level guard, structured WARNING content, single
status line per drop (no Reconnected follow-up), and provider naming.

cli.py

@@ -8267,8 +8267,13 @@ class HermesCLI:
                 logging.getLogger(noisy).setLevel(logging.WARNING)
         else:
             logging.getLogger().setLevel(logging.INFO)
-            for quiet_logger in ('tools', 'run_agent', 'trajectory_compressor', 'cron', 'hermes_cli'):
-                logging.getLogger(quiet_logger).setLevel(logging.ERROR)
+            # NOTE: We deliberately do NOT raise per-logger levels for
+            # tools/run_agent/etc. in quiet mode. Setting logger.setLevel
+            # above the file handler level filters records before they
+            # reach handlers, so agent.log / errors.log lose visibility
+            # into stream-retry events, credential rotations, etc.
+            # Console quietness is enforced by hermes_logging not
+            # installing a console StreamHandler in non-verbose mode.
 
     def _show_insights(self, command: str = "/insights"):
         """Show usage insights and analytics from session history."""