Add Email (IMAP/SMTP) and SSH Remote Access connectors

- CLAUDE.md: developer guide for the marketplace repo
- email/: generic IMAP+SMTP connector (stdlib only, config via env)
  - env[] array, auth.type: password, verify.py (IMAP+SMTP probe)
- ssh/: SSH Remote Access connector ported from Skald, modified
  - ALIASES_FILE → ~/.ssh_aliases.json (was ./secrets/...)
  - optional env[] (TTL/timeout tunables)
  - auth.type: none (per-alias auth at runtime via elicitation)
- tavily/: restructured with env[] (tavilyApiKey), verify.py, auth block
- connectors.json: added email, ssh, and tavily verify.py entries
- SKALD.md: documented env[], verify, password auth, SSH connector

connectors/tavily/connector.json

@@ -4,12 +4,27 @@
   "version": "1.0.0",
   "type": "mcp_remote",
   "mcp_config": {
-    "url": "https://mcp.tavily.com/mcp/?tavilyApiKey={key}",
+    "url": "https://mcp.tavily.com/mcp/?tavilyApiKey={SECRET:tavilyApiKey}",
     "transport": "streamable-http"
   },
   "requires": [
-    "API_KEY"
+    "API_KEY",
+    "ENV"
   ],
+  "env": [
+    {
+      "name": "tavilyApiKey",
+      "label": "Tavily API key",
+      "description": "Your Tavily API key (find it at https://app.tavily.com). Used both as the MCP URL query parameter and for the verification request.",
+      "required": true,
+      "secret": true,
+      "example": "tvly-xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
+    }
+  ],
+  "verify": {
+    "command": "python3 verify.py",
+    "timeout_secs": 15
+  },
   "docs": [
     {
       "lang": "en",