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/types/index.ts

@@ -598,6 +598,27 @@ export type CustomToolRecord = {
     | { kind: "prompt"; config: CustomToolPromptConfig }
 );
 
+/**
+ * A `skills` row: a runbook a bot loads when it applies.
+ */
+export type SkillRecord = {
+    id: number;
+    name: string;
+    slug: string;
+    description: string;
+    body: string;
+    all_bots: boolean;
+    enabled: boolean;
+};
+
+/**
+ * A skill as the Skills settings page shows it: nothing secret in one, so
+ * it's the row with who gets it instead of `all_bots`.
+ */
+export type PublicSkill = Omit<SkillRecord, "all_bots"> & {
+    access: ExtensionAccess;
+};
+
 /**
  * An MCP server as the MCPs settings page shows it. Only super admins get
  * how it's reached (`url`, `headers`, `command`, `setup_command`, `env`).
@@ -650,7 +671,7 @@ export type ExtensionTargets = {
  * composer show it.
  */
 export type BotExtension = {
-    kind: "mcp" | "tool";
+    kind: "mcp" | "tool" | "skill";
     id: number;
     name: string;
     description: string;
@@ -668,12 +689,12 @@ export type BotExtension = {
 };
 
 /**
- * A bot's MCP servers and tools, and what can be added. Only super admins
+ * A bot's MCP servers, tools and skills, and what can be added. Only super admins
  * and admins (the super admin alone for the coordinator) manage them.
  */
 export type BotExtensionsPayload = {
     attached: BotExtension[];
-    addable: { kind: "mcp" | "tool"; id: number; name: string }[];
+    addable: { kind: "mcp" | "tool" | "skill"; id: number; name: string }[];
     can_manage: boolean;
 };
 
@@ -681,6 +702,10 @@ export type McpServersOverviewPayload = ExtensionTargets & {
     servers: PublicMcpServer[];
 };
 
+export type SkillsOverviewPayload = ExtensionTargets & {
+    skills: PublicSkill[];
+};
+
 export type CustomToolsOverviewPayload = ExtensionTargets & {
     tools: PublicCustomTool[];
 };
@@ -1016,6 +1041,7 @@ export type PagePropsType = {
     push_overview?: PushOverview | null;
     mcps_overview?: McpServersOverviewPayload | null;
     tools_overview?: CustomToolsOverviewPayload | null;
+    skills_overview?: SkillsOverviewPayload | null;
     bot_extensions?: BotExtensionsPayload | null;
     /**
      * The files browser's folders (a user's own crew and media, and what a