Rename Installation to Instance

Follows the portal: the noun is "instance" everywhere the app says it —
UI strings, CLI output, error details, docs and comments. The wire keys
(`instance_id`, `instance_token`) and the hub route this calls move with it.

An existing cloud.json is adopted rather than refused: without the key
alias the dataclass fails to parse, which the caller swallows and reads as
"never enrolled" instead of "reconnect".

`instance_key` on a node type becomes `target_key`. It means the outside
thing a node points at, which is a different sense of the word, and keeping
both would put two meanings of "instance" in one codebase.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015YrQnKV3bnQd4K342y8tKj

frontend/src/components/Common/ConnectionNotice.tsx

@@ -9,7 +9,7 @@ import { isPortal } from "@/lib/portal"
 const ID = "connection-offline"
 
 /**
- * Says when the installation cannot be reached, and when it was last heard
+ * Says when the instance cannot be reached, and when it was last heard
  * from.
  *
  * Only ever meaningful under a portal: a local install cannot lose contact with
@@ -39,8 +39,8 @@ export function ConnectionNotice() {
     }
     notify(
       connection.lastSeen
-        ? `Installation offline — last seen ${ago(connection.lastSeen / 1000)}, reconnecting…`
-        : "Installation offline — reconnecting…",
+        ? `Instance offline — last seen ${ago(connection.lastSeen / 1000)}, reconnecting…`
+        : "Instance offline — reconnecting…",
       "warning",
       { id: ID, persistent: true },
     )

frontend/src/components/Common/DashboardMosaic.tsx

@@ -19,8 +19,8 @@ const DEFAULT_COLUMNS = 12
  * How many tiles are worth a request of their own.
  *
  * ponytail: the list endpoint carries no placements, so a footprint means
- * reading that dashboard's document — cheap for the handful an installation
- * has, and shared with the editor's own cache. The ceiling is an installation
+ * reading that dashboard's document — cheap for the handful an instance
+ * has, and shared with the editor's own cache. The ceiling is an instance
  * with dozens: the tiles past this show their name and nothing else, and the
  * fix would be a stored footprint on `DashboardSummary`.
  */

frontend/src/components/Common/GlobalSearch.tsx

@@ -58,7 +58,7 @@ function hint(entry: SearchEntry): string {
 }
 
 /**
- * Everything in this installation, by name, from anywhere.
+ * Everything in this instance, by name, from anywhere.
  *
  * The whole index arrives in one fetch and `cmdk` does the matching, so results
  * narrow as they are typed without a round trip per keystroke.
@@ -190,7 +190,7 @@ export function GlobalSearch({
           </>
         ) : (
           <p className="py-6 text-center text-sm text-muted-foreground">
-            Start typing to search this installation.
+            Start typing to search this instance.
           </p>
         )}
       </CommandList>

frontend/src/components/Common/Notifications.tsx

@@ -3,7 +3,7 @@
  *
  * A single stack at the top centre, over whatever is below it. Newest on top,
  * each card going on its own after a few seconds unless it was raised as
- * persistent — an offline notice stays until the installation answers again.
+ * persistent — an offline notice stays until the instance answers again.
  *
  * Raised from anywhere through `notify()` in `lib/notificationStore`, which is
  * where the semantics live; this only draws them.

frontend/src/components/Common/OverviewToolbar.tsx

@@ -303,10 +303,10 @@ export function ConfirmDelete({
           <DialogDescription>
             {description ?? (
               <>
-                {names.length === 1 ? "It goes" : "They go"} from the
-                installation at once. The store's git history keeps what was
-                there, but nothing in the app brings{" "}
-                {names.length === 1 ? "it" : "them"} back.
+                {names.length === 1 ? "It goes" : "They go"} from the instance
+                at once. The store's git history keeps what was there, but
+                nothing in the app brings {names.length === 1 ? "it" : "them"}{" "}
+                back.
               </>
             )}
           </DialogDescription>