Add or move a docs page

A page is not finished when the MDX file exists. It also needs a navigation entry, and a move or deletion needs a redirect. CI enforces both.

Read AGENTS.md for the navigation map, the style guide, and the frontmatter rules. This skill covers the procedure around them and does not repeat them.

Step 1. Choose the source directory

Use the "Source directory summary" table in AGENTS.md to go from subject to directory. Two traps:

• Directory names do not match navigation names. src/langsmith/fleet/ appears as "No-code agents"; src/langsmith/managed-deep-agents*.mdx appears under Build, not under a LangSmith menu.
• Lifecycle menus mix products. Build draws from both src/oss/ and src/langsmith/; Test, Deploy, and Monitor all draw from src/langsmith/.