fix(dotter): add missing variables to default profile

[zenibako]

The pipeline was failing because several variables used in template files
were not defined in the default.variables section, causing deployments to
fail when the default profile was tested.

Added missing variables to default.variables:

• mcp_atlassian_enabled, mcp_gitlab_enabled, mcp_postman_enabled,
  mcp_salesforce_enabled, mcp_sonarqube_enabled (all defaulting to false)
• lsp_salesforce_disabled (defaulting to true)
• opencode_build_agent_model and opencode_plan_agent_model

Removed duplicate variable definitions from personal.variables that
matched the default values, keeping only the actual overrides
(playdate_sdk_enabled).

This ensures all profiles can be deployed successfully without requiring
variable overrides in local.toml.