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",

connectors/tavily/verify.py

@@ -0,0 +1,65 @@
+#!/usr/bin/env python3
+"""Verify the Tavily API key by making a minimal search request.
+
+Reads TAVILY_API_KEY from the environment (the key skald collected from the
+user and substituted into the {SECRET:tavilyApiKey} placeholder), POSTs a
+minimal search to https://api.tavily.com/search, and prints a single JSON
+object on stdout:
+
+    {"ok": true,  "message": "Tavily API key is valid"}
+    {"ok": false, "message": "Tavily API key is invalid or unauthorized"}
+
+Exit code is 0 on success, 1 on any failure. The API key is never printed.
+
+stdlib only (urllib).
+"""
+import json
+import os
+import sys
+import urllib.error
+import urllib.request
+
+
+def _result(ok, message):
+    print(json.dumps({"ok": ok, "message": message}))
+    sys.exit(0 if ok else 1)
+
+
+def main():
+    api_key = os.environ.get("tavilyApiKey", "").strip()
+    if not api_key:
+        # Also accept the UPPER_SNAKE form some users may type.
+        api_key = os.environ.get("TAVILY_API_KEY", "").strip()
+    if not api_key:
+        _result(False, "No Tavily API key provided (tavilyApiKey env var is empty)")
+
+    body = json.dumps({
+        "api_key": api_key,
+        "query": "skald connectivity check",
+        "max_results": 1,
+        "search_depth": "basic",
+    }).encode("utf-8")
+
+    req = urllib.request.Request(
+        "https://api.tavily.com/search",
+        data=body,
+        headers={"Content-Type": "application/json"},
+        method="POST",
+    )
+
+    try:
+        with urllib.request.urlopen(req, timeout=15) as resp:
+            if 200 <= resp.status < 300:
+                _result(True, "Tavily API key is valid")
+            _result(False, f"Tavily returned HTTP {resp.status}")
+    except urllib.error.HTTPError as e:
+        if e.code in (401, 403):
+            _result(False, "Tavily API key is invalid or unauthorized "
+                           f"(HTTP {e.code})")
+        _result(False, f"Tavily returned HTTP {e.code}: {e.reason}")
+    except Exception as e:
+        _result(False, f"Tavily verify request failed: {e}")
+
+
+if __name__ == "__main__":
+    main()