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/bitbucket.toml

@@ -0,0 +1,35 @@
+id = "bitbucket"
+name = "Bitbucket"
+description = "Access Bitbucket repositories, pull requests, and pipelines through the MCP server"
+category = "devtools"
+icon = "🪣"
+tags = ["git", "vcs", "code", "pull-requests", "ci", "atlassian"]
+
+[transport]
+type = "stdio"
+command = "npx"
+args = ["-y", "@atlassian-mcp-server/bitbucket"]
+
+[[required_env]]
+name = "BITBUCKET_USERNAME"
+label = "Bitbucket Username"
+help = "Your Bitbucket Cloud username (not email)"
+is_secret = false
+get_url = "https://bitbucket.org/account/settings/"
+
+[[required_env]]
+name = "BITBUCKET_APP_PASSWORD"
+label = "Bitbucket App Password"
+help = "An app password with repository and pull request permissions"
+is_secret = true
+get_url = "https://bitbucket.org/account/settings/app-passwords/"
+
+[health_check]
+interval_secs = 60
+unhealthy_threshold = 3
+
+setup_instructions = """
+1. Go to Bitbucket > Personal Settings > App passwords (https://bitbucket.org/account/settings/app-passwords/).
+2. Create an app password with 'Repositories: Read/Write' and 'Pull requests: Read/Write' permissions.
+3. Enter your Bitbucket username and paste the app password into the fields above.
+"""