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_lg.svg

@@ -0,0 +1,6 @@
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+  <rect width="96" height="96" rx="14" fill="#1e293b"/>
+  <text x="48" y="55" font-family="monospace" font-size="40" fill="#22d3ee" text-anchor="middle" font-weight="bold">SSH</text>
+  <line x1="20" y1="70" x2="76" y2="70" stroke="#334155" stroke-width="2"/>
+  <rect x="28" y="60" width="40" height="2" rx="1" fill="#22d3ee" opacity="0.5"/>
+</svg>