Give bots skills: runbooks they load when a job matches

A skill is a runbook: a name, a unique slug, a one-line description of when
it applies, and the markdown body. A run only ever sees the slug and
description (one load_skill tool carries them), and reads the whole body
only when it calls the tool, so a long runbook costs nothing until needed.

Skills are the third extension kind beside MCP servers and custom tools, on
the same botExtensionsSql path, so per-bot, per-workspace and all-bots
grants work the same way, and attachDefaultExtensions hands an every-bot
skill to new bots. load_skill is a reserved tool name, so a custom tool
cannot shadow it, and a built-in wins a clash.

Managed on Settings > Skills; ExtensionRow links each kind to its own page
and a skill never reports a failure, since nothing connects or runs.

src/utils/extension-noun.ts

@@ -0,0 +1,36 @@
+import type { BotExtension } from "@/src/types";
+
+type Params = {
+    kind: BotExtension["kind"];
+    /**
+     * With the article, for a sentence: "the tool", "the MCP server".
+     */
+    article?: boolean;
+};
+
+/**
+ * What an extension kind is called in copy: a tool, an MCP server or a
+ * skill.
+ */
+export default function extensionNoun({ kind, article }: Params) {
+    const noun = kind == "mcp" ? "MCP server" : kind == "skill" ? "skill" : "tool";
+
+    return article ? `the ${noun}` : noun;
+}
+
+type TitleParams = {
+    kind: BotExtension["kind"];
+    /**
+     * What happened, in one word: "added", "removed".
+     */
+    verb: string;
+};
+
+/**
+ * A log entry's title: "MCP server added", "Skill removed".
+ */
+export function extensionLogTitle({ kind, verb }: TitleParams) {
+    const noun = extensionNoun({ kind });
+
+    return `${noun.charAt(0).toUpperCase()}${noun.slice(1)} ${verb}`;
+}