feat: sync content definitions from core repo

Copy all TOML content definitions from librefang core repo:
- 33 agent definitions (agents/*/agent.toml)
- 14 hand definitions with docs (hands/*/HAND.toml + SKILL.md)
- 25 integration templates (integrations/*.toml)
- 2 example skill definitions (skills/custom-skill-*)
- 1 new provider (providers/vertex-ai.toml)

Part of the framework-vs-content registry split (RFC v0.7).

integrations/sentry.toml

@@ -0,0 +1,35 @@
+id = "sentry"
+name = "Sentry"
+description = "Monitor and manage Sentry error tracking, issues, and releases through the MCP server"
+category = "devtools"
+icon = "🐛"
+tags = ["monitoring", "errors", "debugging", "observability", "apm"]
+
+[transport]
+type = "stdio"
+command = "npx"
+args = ["-y", "@sentry/mcp-server"]
+
+[[required_env]]
+name = "SENTRY_AUTH_TOKEN"
+label = "Sentry Auth Token"
+help = "An authentication token with project:read and event:read scopes"
+is_secret = true
+get_url = "https://sentry.io/settings/account/api/auth-tokens/"
+
+[[required_env]]
+name = "SENTRY_ORG_SLUG"
+label = "Sentry Organization Slug"
+help = "Your Sentry organization slug (found in Settings > General)"
+is_secret = false
+get_url = ""
+
+[health_check]
+interval_secs = 60
+unhealthy_threshold = 3
+
+setup_instructions = """
+1. Go to Sentry > Settings > Auth Tokens (https://sentry.io/settings/account/api/auth-tokens/) and create a new token with 'project:read' and 'event:read' scopes.
+2. Find your organization slug in Sentry > Settings > General Settings.
+3. Paste the auth token and organization slug into the fields above.
+"""