Show when each extension was last updated

MCP, skill and tool rows in Settings say "Updated 5m ago" beside how
they're reached and who gets them. updated_at now means a change to an
extension's settings (an edit, or any Access save): runs, connections and
MCP syncs keep their own last_checked_at / last_synced_at and no longer
touch it.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/utils/describe-skill-proposal.test.ts

@@ -10,6 +10,7 @@ const current: SkillRecord = {
     body: "1. Search the client's rankings.\n2. Write the report.\n3. Attach it.",
     all_bots: false,
     enabled: true,
+    updated_at: null,
 };
 
 describe("describeSkillProposal", () => {

src/utils/skill-proposal-changes.test.ts

@@ -10,6 +10,7 @@ const current: SkillRecord = {
     body: "1. Install Baileys.\n2. Pair.",
     all_bots: false,
     enabled: true,
+    updated_at: null,
 };
 
 describe("skillProposalChanges", () => {