Update(procmon-plugin): Add keyboard navigation and reduce CPU sampling (#321)

* Add procmon plugin with live process panel

New Noctalia plugin: bar widget shows CPU/RAM usage and process
count; floating panel has a sortable, searchable process table
with per-process kill. Background service samples ps and /proc
stats and publishes via plugin state.

* Throttle data-driven panel renders

Rebuild table at most every 500ms to stay within the panel update
CPU budget. User interactions still render immediately; only state
watches and the tick go through maybeRender().

* Update procmon deps and fix timestamp precision

Document head, grep, and cat as required commands. Correct refresh
interval default to 1000 ms. Sample refreshedAtMs in milliseconds.

* Add keyboard navigation and reduce CPU sampling

- Panel: arrow keys move cursor, Ctrl+D kills selected, Ctrl+F focuses
  filter
- Service: sample /proc stats every 1s, ps every 2s; 2s render floor
- Widget: handle vertical bars, truncate text, use valid theme color
- Bump version to 0.4.0, plugin_api 13

procmon/translations/en.json

@@ -1,59 +1,60 @@
 {
-  "panel": {
-    "col": {
-      "cmd": "COMMAND",
-      "cpu": "CPU%",
-      "cpu_raw": "CPU",
-      "mem": "MEM%",
-      "mem_raw": "MEM",
-      "pid": "PID",
-      "rss": "RSS",
-      "stat": "S"
-    },
-    "count": "{n} processes",
-    "kill_tip": "Kill {pid}",
-    "load": "Load",
-    "no_processes": "No matching processes",
-    "refresh": "Refresh",
-    "refreshed_at": "Updated {time}",
-    "search_placeholder": "Filter by name, user or PID",
-    "sort_asc": "asc",
-    "sort_desc": "desc",
-    "title": "Processes"
-  },
   "settings": {
-    "glyph": {
-      "description": "Glyph shown in the bar widget.",
-      "label": "Widget icon"
-    },
-    "icon_only": {
-      "description": "Show only a CPU icon in the bar widget; details move to the tooltip.",
-      "label": "Icon only"
-    },
-    "kill_command": {
-      "description": "Command run against a selected PID (the PID is appended). Empty uses kill -TERM.",
-      "label": "Kill command"
-    },
     "refresh_interval": {
-      "description": "How often the process list is resampled.",
-      "label": "Refresh interval (ms)"
-    },
-    "show_count": {
-      "description": "Append the number of processes to the bar widget text.",
-      "label": "Show process count"
+      "label": "Refresh interval (ms)",
+      "description": "How often the process list is resampled."
     },
     "sort_by": {
-      "description": "Column the process table is sorted by when the panel opens.",
       "label": "Default sort column",
+      "description": "Column the process table is sorted by when the panel opens.",
       "options": {
-        "cmd": "Command",
         "cpu": "CPU",
         "mem": "Memory",
-        "pid": "PID"
+        "pid": "PID",
+        "cmd": "Command"
       }
+    },
+    "kill_command": {
+      "label": "Kill command",
+      "description": "Command run against a selected PID (the PID is appended). Empty uses kill -TERM."
+    },
+    "show_count": {
+      "label": "Show process count",
+      "description": "Append the number of processes to the bar widget text."
+    },
+    "glyph": {
+      "label": "Widget icon",
+      "description": "Glyph shown in the bar widget."
+    },
+    "icon_only": {
+      "label": "Icon only",
+      "description": "Show only a CPU icon in the bar widget; details move to the tooltip."
     }
   },
   "widget": {
     "tooltip": "CPU {cpu}%  RAM {ram}%  ·  {n} processes"
+  },
+  "panel": {
+    "title": "Processes",
+    "refreshed_at": "Updated {time}",
+    "refresh": "Refresh",
+    "load": "Load",
+    "search_placeholder": "Filter by name, user or PID",
+    "sort_asc": "asc",
+    "sort_desc": "desc",
+    "col": {
+      "pid": "PID",
+      "cpu": "CPU%",
+      "cpu_raw": "CPU",
+      "mem": "MEM%",
+      "mem_raw": "MEM",
+      "rss": "RSS",
+      "stat": "S",
+      "cmd": "COMMAND"
+    },
+    "count": "{n} processes",
+    "no_processes": "No matching processes",
+    "kill_tip": "Kill {pid}",
+    "keys_hint": "Ctrl+F filter · Ctrl+D kill selected · arrows move"
   }
 }