feat: add email outreach CLIs for backlink building

Add 4 new zero-dependency CLI tools for email outreach:
- hunter.js: Email finding/verification via Hunter.io (query param auth)
- snov.js: Email finding + drip campaigns via Snov.io (OAuth2 auth)
- lemlist.js: Cold email campaigns via Lemlist (Basic auth)
- instantly.js: Cold email at scale via Instantly.ai (query param auth)

Includes integration guides and registry/README updates.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tools/integrations/instantly.md

@@ -0,0 +1,104 @@
+# Instantly.ai
+
+Cold email platform with built-in email warmup and campaign management at scale.
+
+## Capabilities
+
+| Integration | Available | Notes |
+|-------------|-----------|-------|
+| API | ✓ | REST API for campaigns, leads, accounts, analytics |
+| MCP | - | Not available |
+| CLI | [✓](../clis/instantly.js) | Zero-dependency Node.js CLI |
+| SDK | - | API-only |
+
+## Authentication
+
+- **Type**: API Key (query parameter)
+- **Parameter**: `api_key={key}`
+- **Env var**: `INSTANTLY_API_KEY`
+- **Get key**: [Instantly Settings > Integrations > API](https://app.instantly.ai/app/settings/integrations)
+
+## Common Agent Operations
+
+### Manage campaigns
+
+```bash
+# List campaigns
+node tools/clis/instantly.js campaigns list --limit 20
+
+# Get campaign details
+node tools/clis/instantly.js campaigns get --id cam_abc123
+
+# Check campaign status
+node tools/clis/instantly.js campaigns status --id cam_abc123
+
+# Launch a campaign
+node tools/clis/instantly.js campaigns launch --id cam_abc123
+
+# Pause a campaign
+node tools/clis/instantly.js campaigns pause --id cam_abc123
+```
+
+### Manage leads
+
+```bash
+# List leads in a campaign
+node tools/clis/instantly.js leads list --campaign-id cam_abc123 --limit 50
+
+# Add a lead
+node tools/clis/instantly.js leads add --campaign-id cam_abc123 --email john@example.com --first-name John --last-name Doe --company "Example Inc"
+
+# Delete a lead
+node tools/clis/instantly.js leads delete --campaign-id cam_abc123 --email john@example.com
+
+# Check lead status
+node tools/clis/instantly.js leads status --campaign-id cam_abc123 --email john@example.com
+```
+
+### Manage email accounts
+
+```bash
+# List connected accounts
+node tools/clis/instantly.js accounts list --limit 20
+
+# Check account status
+node tools/clis/instantly.js accounts status --account-id me@example.com
+
+# Check warmup status
+node tools/clis/instantly.js accounts warmup-status --account-id me@example.com
+```
+
+### View analytics
+
+```bash
+# Campaign analytics
+node tools/clis/instantly.js analytics campaign --campaign-id cam_abc123 --start 2024-01-01 --end 2024-01-31
+
+# Step-by-step analytics
+node tools/clis/instantly.js analytics steps --campaign-id cam_abc123
+
+# Account-level analytics
+node tools/clis/instantly.js analytics account --start 2024-01-01 --end 2024-01-31
+```
+
+### Manage blocklist
+
+```bash
+# List blocked emails/domains
+node tools/clis/instantly.js blocklist list
+
+# Add to blocklist
+node tools/clis/instantly.js blocklist add --entries "competitor.com,spam@example.com"
+```
+
+## Rate Limits
+
+- API rate limits vary by plan
+- Recommended: stay under 10 requests/second
+
+## Use Cases
+
+- **Link building at scale**: Run large-volume outreach campaigns with built-in warmup
+- **Campaign management**: Launch, pause, and monitor cold email campaigns
+- **Account health**: Monitor email account warmup and deliverability
+- **Analytics**: Track open rates, reply rates, and campaign performance