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/ssh/icon_sm.svg

@@ -0,0 +1,4 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 48 48" width="48" height="48">
+  <rect width="48" height="48" rx="8" fill="#1e293b"/>
+  <text x="24" y="30" font-family="monospace" font-size="22" fill="#22d3ee" text-anchor="middle">SSH</text>
+</svg>