sketch: add session history tools using markdown table API

Add session history tools to allow the LLM to access previous sketch sessions:
- New list_recent_sketch_sessions and read_sketch_session tools
- Integration with skaband client for session data retrieval
- Session history tools automatically added when skaband client available
- Updated agent configuration to include skaband client
- Client handles plain text markdown table response from API
- Display server-generated markdown table directly to LLM

Co-Authored-By: sketch <hello@sketch.dev>
Change-ID: s693acdfdaaa392c8k
diff --git a/termui/termui.go b/termui/termui.go
index bbe04b4..512fa65 100644
--- a/termui/termui.go
+++ b/termui/termui.go
@@ -81,6 +81,10 @@
  ๐Ÿ“œ Console logs
 {{else if eq .msg.ToolName "browser_clear_console_logs" -}}
  ๐Ÿงน Clear console logs
+{{else if eq .msg.ToolName "list_recent_sketch_sessions" -}}
+ ๐Ÿ“š List recent sketch sessions
+{{else if eq .msg.ToolName "read_sketch_session" -}}
+ ๐Ÿ“– Read session {{.input.session_id}}
 {{else -}}
  ๐Ÿ› ๏ธ  {{ .msg.ToolName}}: {{.msg.ToolInput -}}
 {{end -}}