refactor(workflow): migrate to .sourcegraph config directory

- Update file paths for custom workflow nodes, commit templates, and system instructions to use `.sourcegraph` instead of `.cody`.
- Modify the retrieval of custom system instructions and commit templates to use the new `.sourcegraph/prompts` directory.
- Adjust the `ruleSearchPaths` function to only search the specific path for rules, removing the need to traverse the directory tree.
- Update workflow file paths to use `.sourcegraph/workflows` directory.
- Update node file paths to use `.sourcegraph/nodes` directory.
- Bump version to 1.74.0+2

Author: PriNova

vscode/package.json

@@ -3,7 +3,7 @@
   "name": "cody-ai",
   "private": true,
   "displayName": "Cody: AI Code Assistant",
-  "version": "1.74.0+1",
+  "version": "1.74.0+2",
   "publisher": "sourcegraph",
   "license": "Apache-2.0",
   "icon": "resources/sourcegraph.png",