feat: right-click menus in Files/Users/Artifacts; several SSH keys and accounts per host

- Files: right-click a sidebar workspace (Open, Copy path) or home (Open,
  Open Trash), a path crumb (Open, Download as zip, Paste into, Copy path),
  a Trash row (Restore, Copy path, Delete forever), the Trash area (Refresh,
  Empty Trash) and an admin's per-user Trash folder (Open, Empty Trash).
- Users: row menu (Edit + Open home in Files for an admin, Copy username/email).
- Artifacts: card menu repeating its buttons, plus Copy link for a page.
- Git identity: named SSH keys beside the default ones (id_<type>_<name>,
  max 10, DELETE ?id=); SSH logins per alias (`ssh://<alias>/` →
  `ssh://<user>@<host>/`, so several AWS CodeCommit accounts share a host),
  each optionally tied to one key (`agenthub.<from>.sshKey`) — a clone of
  that URL offers only that key and persists it. Terminal sshCommand follows
  the keys. Settings → Git: "More SSH keys" + account name/key in the AWS and
  other-host forms. Docs/API.md, OpenAPI updated.

server/openapi-extra/files.js

@@ -276,17 +276,23 @@ const paths = {
   "/api/me/git/ssh-key": {
     post: {
       tags: ["Git identity"],
-      summary: "Make (or with `replace`, replace) the SSH key of `type`; the other type is kept",
+      summary:
+        "Make (or with `replace`, replace) the default SSH key of `type`, or with `name` one more beside it",
       operationId: "generateSshKey",
       requestBody: json({
         replace: { type: "boolean" },
         type: { type: "string", enum: ["ed25519", "rsa"] },
+        name: { type: "string", pattern: "^[a-z0-9][a-z0-9-]{0,31}$" },
       }),
-      responses: { 201: { description: "The identity." } },
+      responses: {
+        201: { description: "The identity." },
+        400: { description: "EBADKEYNAME" },
+        409: { description: "EEXISTS (without replace, or the name is taken) / ETOOMANYKEYS" },
+      },
     },
     delete: {
       tags: ["Git identity"],
-      summary: "Delete the SSH key of ?type=ed25519|rsa, or every key",
+      summary: "Delete one SSH key (?id=, or the default of ?type=ed25519|rsa), or every key",
       operationId: "deleteSshKey",
       parameters: [
         {
@@ -295,6 +301,7 @@ const paths = {
           required: false,
           schema: { type: "string", enum: ["ed25519", "rsa"] },
         },
+        { name: "id", in: "query", required: false, schema: { type: "string" } },
       ],
       responses: { 200: { description: "The identity." } },
     },
@@ -311,6 +318,36 @@ const paths = {
       },
     },
   },
+  "/api/me/git/ssh-user": {
+    put: {
+      tags: ["Git identity"],
+      summary:
+        "An SSH login: url.<ssh://user@host/>.insteadOf ssh://<alias or host>/, optionally tied to one key",
+      operationId: "setSshUser",
+      requestBody: json(
+        {
+          host: { type: "string" },
+          user: { type: "string" },
+          alias: { type: "string", pattern: "^[a-z0-9][a-z0-9-]{0,62}$" },
+          key: { type: "string" },
+        },
+        ["host", "user"]
+      ),
+      responses: {
+        200: { description: "The identity; `sshUsers: [{host, user, alias, key}]`." },
+        400: { description: "EBADHOST / EBADSSHUSER / EBADALIAS / ENOKEY" },
+      },
+    },
+  },
+  "/api/me/git/ssh-user/{from}": {
+    delete: {
+      tags: ["Git identity"],
+      summary: "Drop the SSH login of a host or alias (and its key link)",
+      operationId: "deleteSshUser",
+      parameters: [{ name: "from", in: "path", required: true, schema: { type: "string" } }],
+      responses: { 200: { description: "The identity." }, 404: { description: "ENOTFOUND" } },
+    },
+  },
   "/api/me/git/https": {
     post: {
       tags: ["Git identity"],