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/UserSettings/RemoteAccess.tsx

@@ -31,19 +31,19 @@ type CloudStatus = {
   connected: boolean
   portal_url: string | null
   portal_account: string | null
-  installation_id: string | null
+  instance_id: string | null
   last_error: string | null
   connected_since: number | null
 }
 
 /**
- * Connecting this installation to a Fluksio portal, or cutting it loose, and
+ * Connecting this instance to a Fluksio portal, or cutting it loose, and
  * admitting other portal accounts to it.
  *
  * Deliberately blunt about what it grants: the account that enrolled is what
  * the portal owner's sessions act as, and this screen says which one. Anyone
  * else gets in only by being added here, as a local user of their own.
- * Everything here is optional — an installation nobody enrolls never contacts
+ * Everything here is optional — an instance nobody enrolls never contacts
  * anything.
  */
 export function RemoteAccess() {
@@ -108,8 +108,8 @@ export function RemoteAccess() {
       <CardHeader>
         <CardTitle>Remote access</CardTitle>
         <CardDescription>
-          Reach this installation from fluksio.com. Entirely optional — without
-          it, this installation talks to nothing outside your network.
+          Reach this instance from fluksio.com. Entirely optional — without it,
+          this instance talks to nothing outside your network.
         </CardDescription>
       </CardHeader>
       <CardContent className="flex flex-col gap-6">
@@ -133,9 +133,9 @@ export function RemoteAccess() {
                     own user.
                   </span>
                 </Field>
-                <Field label="Installation">
+                <Field label="Instance">
                   <span className="font-mono text-xs">
-                    {status.installation_id ?? "—"}
+                    {status.instance_id ?? "—"}
                   </span>
                 </Field>
               </dl>
@@ -156,8 +156,8 @@ export function RemoteAccess() {
               <div>
                 <h3 className="font-medium">Remote users</h3>
                 <p className="text-sm text-muted-foreground">
-                  Let someone else reach this installation through the portal.
-                  They get a user of their own here — not yours, and never a
+                  Let someone else reach this instance through the portal. They
+                  get a user of their own here — not yours, and never a
                   superuser, so they cannot pass access on.
                 </p>
               </div>
@@ -173,9 +173,9 @@ export function RemoteAccess() {
                   }
                 />
                 <p className="text-xs text-muted-foreground">
-                  They get a code at fluksio.com → Installations → Join an
-                  installation. Added users appear under Admin → Users; deleting
-                  them there ends their access.
+                  They get a code at fluksio.com → Instances → Join an instance.
+                  Added users appear under Admin → Users; deleting them there
+                  ends their access.
                 </p>
               </div>
               <div>
@@ -210,7 +210,7 @@ export function RemoteAccess() {
                 onChange={(event) => setCode(event.target.value.toUpperCase())}
               />
               <p className="text-xs text-muted-foreground">
-                Get a code at fluksio.com → Installations → Add installation.
+                Get a code at fluksio.com → Instances → Add instance.
               </p>
             </div>
             <div>
@@ -235,8 +235,8 @@ export function RemoteAccess() {
             <DialogTitle>Disconnect from the portal?</DialogTitle>
             <DialogDescription>
               Remote access ends immediately and the portal's credentials stop
-              working here. Nothing on this installation is changed or deleted,
-              and you can connect again with a new code.
+              working here. Nothing on this instance is changed or deleted, and
+              you can connect again with a new code.
             </DialogDescription>
           </DialogHeader>
           <DialogFooter>