feat(core): per-workspace Agent Skills listed in the system prompt, /skills in Telegram

Skills live in <cwd>/.claude/skills/<name>/SKILL.md (frontmatter name + description).
SkillCatalog re-reads them on every run and the prompt lists name, description and
path; the model reads the full SKILL.md with the read tool when a task matches.

hosts/Volcanic.AgenticCore.Telegram/Chats/ChatCommands.cs

@@ -8,6 +8,7 @@ using Volcanic.AgenticCore.A2A.Server.Tasks;
 using Volcanic.AgenticCore.Abstractions.Providers;
 using Volcanic.AgenticCore.Extensions.A2A;
 using Volcanic.AgenticCore.Extensions.Scheduler;
+using Volcanic.AgenticCore.Features.SystemPrompt;
 using Volcanic.AgenticCore.Hosting;
 using Volcanic.AgenticCore.Telegram.Rendering;
 using Volcanic.AgenticCore.Telegram.Scheduling;
@@ -29,6 +30,7 @@ public sealed class ChatCommands(TelegramSender sender, ChatTimeZoneService? zon
         new() { Command = "compact", Description = "Summarise the conversation to free context" },
         new() { Command = "thinking", Description = "Show or set the thinking level" },
         new() { Command = "timezone", Description = "Show or set this chat's time zone" },
+        new() { Command = "skills", Description = "Skills in this chat's workspace" },
         .. SchedulerSetup.Menu,
         TriggersSetup.MenuCommand,
         new() { Command = "a2a", Description = "A2A callers, remote agents and tasks of this chat" },
@@ -122,6 +124,10 @@ public sealed class ChatCommands(TelegramSender sender, ChatTimeZoneService? zon
                 await ReplyAsync(chat, triggers is null ? TriggersSetup.DisabledReply : "**Group triggers**\n" + triggers.Describe(chat.ChatId, chat.Session.TimeZone), cancellationToken).ConfigureAwait(false);
                 return true;
 
+            case "skills":
+                await ReplyAsync(chat, Skills(chat), cancellationToken).ConfigureAwait(false);
+                return true;
+
             case "jobs":
                 await ReplyAsync(chat, Jobs(chat), cancellationToken).ConfigureAwait(false);
                 return true;
@@ -157,6 +163,7 @@ public sealed class ChatCommands(TelegramSender sender, ChatTimeZoneService? zon
         /compact – summarise the conversation to free context
         /thinking [level] – show or set the thinking level
         /timezone [IANA name|reset] – this chat's time zone
+        /skills – skills in my workspace
         """ + SchedulerSetup.HelpLines + "\n/a2a – A2A callers, remote agents and recent tasks of this chat" + TriggersSetup.HelpLines + GoogleCalendarSetup.HelpLines(chat.Session.Commands)
         + (chat.Session.Commands.Any(c => c.Name == "mcp_add") ? RemoteMcpSetup.HelpLines : "");
 
@@ -216,6 +223,14 @@ public sealed class ChatCommands(TelegramSender sender, ChatTimeZoneService? zon
             : error;
     }
 
+    private static string Skills(ChatContext chat)
+    {
+        var skills = SkillCatalog.Load(chat.Session.Cwd);
+        var where = $"`{Path.GetRelativePath(chat.Session.Cwd, SkillCatalog.Directory(chat.Session.Cwd))}/<name>/SKILL.md`";
+        if (skills.Count == 0) return $"No skills yet. Ask me to write one, or put it in {where}.";
+        return $"**Skills** ({where})\n" + string.Join('\n', skills.Select(s => $"• **{s.Name}** – {s.Description}"));
+    }
+
     private string Jobs(ChatContext chat)
     {
         if (scheduler is not { IsStarted: true }) return SchedulerSetup.DisabledReply;