fix(prometheus, syslog): a target or pattern pauses with a Pause/Resume button, not an "on" tick box in its form (#6419)

Monitors, schedules and maintenance plans already pause with a
Pause/Resume button and say "Paused" where they're listed. Prometheus
targets and syslog patterns only had a tick box inside the edit form,
so a target refused by its endpoint couldn't be stopped from its page.

- Both get a Pause/Resume button (target page and list; patterns list)
  posting to /toggle, recorded in the audit log, and a Paused badge.
- The forms lose the tick box. A new one starts running; an edit keeps
  whether it is paused.
- A target's "off" state is now "paused", in its pages and MCP tools.
  A resumed target reads "not scraped yet" until its next scrape, and its
  counter rates start over.

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

tests/plugins/syslog/test_patterns.py

@@ -11,12 +11,12 @@ from plugins.syslog.patterns import PRESETS, PatternError, Tally, key_for, match
 
 def test_a_form_reads_into_a_pattern():
     v = parse_form(MultiDict({"name": " NFS ", "phrases": "nfsd:\n\n  lockd: \n", "max_severity": "3",
-                              "source_id": "", "window_minutes": "60", "enabled": "on"}))
+                              "source_id": "", "window_minutes": "60"}))
     assert v == {"name": "NFS", "phrases": ["nfsd:", "lockd:"], "max_severity": 3, "source_id": None,
-                 "window_minutes": 60, "enabled": True}
+                 "window_minutes": 60}            # paused or not is the toggle's, not the form's (#6419)
     # A window or severity not offered falls back rather than failing.
     v = parse_form(MultiDict({"name": "x", "phrases": "a", "max_severity": "9", "window_minutes": "7"}))
-    assert (v["max_severity"], v["window_minutes"], v["enabled"]) == (None, 15, False)
+    assert (v["max_severity"], v["window_minutes"]) == (None, 15)
 
 
 @pytest.mark.parametrize("form, says", [