put the monitor scope in the url

/system-monitor/:scope, the same shape as /photos: route pair, one Navigate guard after the
hooks, scope list as react-router NavLinks, and both panels reading useParams instead of
agreeing over a `monitor:scope` channel. The Dock's isActive is a startsWith, so its
highlight survives the redirect off the bare route.

docs/navigation-audit.md

@@ -79,7 +79,7 @@ are good building blocks. The **Workspace/Panel framework** contains **zero** ro
 | M7 | `workspaces/components/Combobox.tsx:53` | caller-supplied route | (existing) | shared widget: `href`-bearing options do `navigate(option.href)`; render them as `<Link>`. Every caller inherits the opaque click. |
 | ~~M8~~ | `Layout/Header/UserMenu.tsx` | — | — | **Done.** Removed rather than routed: nothing had ever been built behind `/settings/resources`, so the item was a bounce to `/` dressed as navigation. Its `header.userMenu.resources` locale keys went with it. |
 | M9 | `Screens/Dashboard/Plans/index.tsx:36` | a plan document | `/plans/:name` | native `<select>` → local state; a plan is a real addressable doc. Have the select `navigate()` or use a link list. |
-| M10 | `SystemMonitor/ScopeList.tsx:14` | monitor scope (btop/pm2/docker) | `/system-monitor/:scope` | small fixed set; low urgency but genuinely addressable. |
+| ~~M10~~ | `SystemMonitor/ScopeList.tsx` | monitor scope (btop/pm2/docker) | `/system-monitor/:scope` | **Done.** Route pair + `Navigate` guard; the scope buttons are `NavLink`s and `useMonitorScope` reads `useParams` instead of the channel. The Dock's hand-rolled `isActive` is a `startsWith`, so its highlight survives the redirect. |
 
 **Music** (M-music) and **Soulseek** (M-slsk) are whole-workspace channel apps — pulled out below because each
 is **one design decision** that cascades across many files:
@@ -122,7 +122,6 @@ This is the primary surface to convert to URL-driven selection.
 | `music:cwd` | library location (album/artist/folder) | `/music?path=` | `MusicBrowser/MusicDetail/FavoritesView` |
 | `soulseek:section` | active Soulseek section | `/soulseek/:section` | `SoulseekNav/View/Dashboard/UserMenu` |
 | `soulseek:user` | selected peer | `/soulseek/users/:name` | `UserMenu.tsx:28`, `SoulseekUsers.tsx:34` |
-| `monitor:scope` | monitor scope | `/system-monitor/:scope` | `ScopeList.tsx` (via `shared.ts:15`) |
 | local `useState` selections | search / room / conversation / peer / open file / preview slug | respective nested routes | `SearchView`, `SoulseekRooms`, `SoulseekChat`, `SoulseekUsers`, `CodeEditor/useEditorState`, `PreviewProvider` |
 
 **Excluded — event-bus / refresh signals, NOT selection:** `files:refresh-signal`,
@@ -203,7 +202,7 @@ publishers means changing the chat panel, which is another agent's, so it is wri
 ### Phase 3 — Whole-workspace routing decisions (needs a design call first)
 - [ ] **Music** — decide `/music?path=` (or nested); back `music:cwd` with the URL; rows → `<Link>` (M-music).
 - [ ] **Soulseek** — decide the nested tree `/soulseek/:section` + `/soulseek/{users,search,rooms,chat}/:x`; **S1 decides S2–S7** (M-slsk).
-- [ ] **M10** SystemMonitor scope → `/system-monitor/:scope` (`ScopeList.tsx:14`).
+- [x] **M10** SystemMonitor scope → `/system-monitor/:scope`; `monitor:scope` channel deleted. **Needs runtime test.**
 - [ ] **M9** Plans → `/plans/:name` (`Plans/index.tsx:36`).
 
 ### Phase 4 — Polish + borderline decisions