Config is not exportable/reproducible: ~121 prebuilt Canvas/AI configs exist only in DB

`drush config:status` shows 121 configurations marked "Only in DB" (not exported to `sites/default/sync`), meaning a clean installation from code does not reproduce the pre-built content. Breakdown: 93 `canvas.components.*`, `views.view.canvas_pages`, `editor.editor.canvas_html_block|inline`, `filter.format.canvas_html_block|inline`, `image.style.canvas_avatar|canvas_parametrized_width`, 5 `core.base_field_override.*`, `block.block.mercury_primary_admin_actions`, and AI-related items: `ai.settings`, `ai.external_moderation`, `ai.html_to_markdown.settings`, 9 `ai_agents.ai_agent.*`, `ai_agents.settings`, `canvas_ai.settings`, `mercury.settings`. The `config_ignore` list is currently empty. Additionally, there are 7 `config_snapshot.snapshot.*` items that, by design, should not be exported (they need to be ignored). The fix exports all 121 items and adds ignore rules for the snapshots.