feat: wire remote-desktop plugin into core and rename i18n keys

Repoints core consumers (dispatcher, collab, session-sharing, tab
utils) at the plugin, adds isTabTypeAvailable gating for rdp/vnc/
telnet, widens hostCapability to accept an array, and renames the
guacamole i18n namespace to remoteDesktop.

scripts/copy-bundled-plugins.cjs

@@ -6,11 +6,12 @@
  * tsc only emits .ts, so without a copy step the plugins directory simply
  * would not exist in dist and the loader would find nothing.
  *
- * docker and host-metrics are the exception: their backends are real
- * TypeScript, physically relocated from src/backend/hosts/docker/ and
- * src/backend/hosts/metrics/ rather than kept as hand-written JS, because
- * each is thousands of lines of typed SSH/session logic that is not worth
- * hand-transpiling. tsconfig.plugins.json compiles each plugin backend's
+ * docker, host-metrics and remote-desktop are the exception: their backends
+ * are real TypeScript, physically relocated from src/backend/hosts/docker/,
+ * src/backend/hosts/metrics/ and src/backend/hosts/guacamole/ rather than
+ * kept as hand-written JS, because each is thousands of lines of typed
+ * SSH/session (or, for remote-desktop, guacd protocol) logic that is not
+ * worth hand-transpiling. tsconfig.plugins.json compiles each plugin backend's
  * TypeScript to a sibling .js next to its source. Their imports into core
  * (e.g. "../../../src/backend/utils/logger.js") are written relative to the
  * TypeScript SOURCE tree so tsc can type-check them, since plugins/ is not

scripts/plugin-manifest.schema.json

@@ -154,14 +154,32 @@
           }
         },
         "hostCapability": {
-          "type": "object",
-          "additionalProperties": false,
-          "required": ["key", "labelKey", "editorTab"],
-          "properties": {
-            "key": { "type": "string", "minLength": 1 },
-            "labelKey": { "type": "string", "minLength": 1 },
-            "editorTab": { "type": "string", "minLength": 1 }
-          }
+          "oneOf": [
+            {
+              "type": "object",
+              "additionalProperties": false,
+              "required": ["key", "labelKey", "editorTab"],
+              "properties": {
+                "key": { "type": "string", "minLength": 1 },
+                "labelKey": { "type": "string", "minLength": 1 },
+                "editorTab": { "type": "string", "minLength": 1 }
+              }
+            },
+            {
+              "type": "array",
+              "minItems": 1,
+              "items": {
+                "type": "object",
+                "additionalProperties": false,
+                "required": ["key", "labelKey", "editorTab"],
+                "properties": {
+                  "key": { "type": "string", "minLength": 1 },
+                  "labelKey": { "type": "string", "minLength": 1 },
+                  "editorTab": { "type": "string", "minLength": 1 }
+                }
+              }
+            }
+          ]
         },
         "permissionGroup": {
           "type": "object",

scripts/validate-plugin-manifest.cjs

@@ -396,11 +396,26 @@ function validateContributes(contributes) {
   }
 
   if ("hostCapability" in contributes) {
-    for (const field of ["key", "labelKey", "editorTab"]) {
-      if (!(field in (contributes.hostCapability || {}))) {
-        errors.push(`contributes.hostCapability.${field} is required`);
+    const raw = contributes.hostCapability;
+    const entries = Array.isArray(raw) ? raw : [raw];
+    const seenKeys = new Set();
+    entries.forEach((entry, index) => {
+      const hc = entry || {};
+      const prefix = Array.isArray(raw)
+        ? `contributes.hostCapability[${index}]`
+        : "contributes.hostCapability";
+      for (const field of ["key", "labelKey", "editorTab"]) {
+        if (!(field in hc)) {
+          errors.push(`${prefix}.${field} is required`);
+        }
       }
-    }
+      if (typeof hc.key === "string") {
+        if (seenKeys.has(hc.key)) {
+          errors.push(`${prefix}.key is a duplicate: "${hc.key}"`);
+        }
+        seenKeys.add(hc.key);
+      }
+    });
   }
 
   if ("permissionGroup" in contributes) {