fix: use sentence-case "Agent skill" label and refine note

Address review feedback on the Agent skill target:

- Use sentence case "Agent skill" for the architecture and target labels, the
  enabledArchitectureLabels test, the copilot-studio unavailable-error copy,
  and the catalogue prose line, for consistency with the rest of the UI.
- Set the architecture note to
  "Any AI agent that supports skills — portable, with no host-specific tools."
- Recompute the catalogue SHA-256 lock after the prose edit (version unchanged).

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Author: adilei

common/architecture-registry.test.ts

@@ -62,7 +62,7 @@ test("the manifest derives architecture validation and target availability", ()
   assert.deepEqual(enabledArchitectureLabels("skill"), [
     "Scout",
     "Cowork",
-    "Agent Skill",
+    "Agent skill",
   ]);
   assert.deepEqual(enabledArchitectureLabels("automation"), ["Scout"]);
 });

common/architecture-registry.ts

@@ -120,15 +120,15 @@ export const ARCHITECTURE_MANIFEST = defineArchitectures([
   },
   {
     id: "agent-skill",
-    label: "Agent Skill",
+    label: "Agent skill",
     // Export-only, so this label is never surfaced; kept non-blank for the manifest
     // invariant and as a sensible fallback if the target ever gains an install path.
     installTargetLabel: "your agent",
-    note: "Any AI Agent with Skill support",
+    note: "Any AI agent that supports skills — portable, with no host-specific tools.",
     targets: [
       {
         kind: "skill",
-        label: "Agent Skill",
+        label: "Agent skill",
         enabled: true,
         note:
           "A portable skill you export and load into any agent that supports skills. " +

electron/architectures/catalogue-registry.test.ts

@@ -87,7 +87,7 @@ test("disabled targets stay unavailable even when catalogue content is staged",
   assert.equal(registry.catalogueFor("copilot-studio", "skill"), null);
   assert.throws(
     () => registry.requireCatalogue("copilot-studio", "skill"),
-    /That target architecture isn't available yet\. Choose Scout, Cowork, or Agent Skill\./,
+    /That target architecture isn't available yet\. Choose Scout, Cowork, or Agent skill\./,
   );
 });
 
@@ -206,6 +206,6 @@ test("real providers preserve versions, content, and the support matrix", () =>
   assert.equal(agentSkillSkill.version, "2026-08-06");
   assert.equal(
     sha256(agentSkillSkill.content),
-    "d5cd96cd8917710aa27b2430358472d947a3cdf3be611cb8f8484d5df2b72789",
+    "27cb863efb3fe973d3b7d4e24359cf5297c1b30fdbc29c073878b57a6d5d8810",
   );
 });

electron/architectures/catalogues/agent-skill-catalogue.ts

@@ -12,7 +12,7 @@ export const AGENT_SKILL_CATALOGUE_VERSION = "2026-08-06";
 const AGENT_SKILL_CATALOGUE = `
 # Target: Any AI agent with skill support — generic skill catalogue (portable capabilities only)
 
-An **Agent Skill** is a portable \`SKILL.md\` file: optional YAML frontmatter followed by a
+An **Agent skill** is a portable \`SKILL.md\` file: optional YAML frontmatter followed by a
 markdown **instructions body** (the standard Copilot skill shape). It targets no specific
 host, so it must NOT assume any proprietary built-in tools.