Update documentation for new commands and output formats

- Update README.md with new commands summary and uv development workflow
- Add docs/exploring.md covering databases, tables, schema, rows, get
  commands with filtering, sorting, pagination, and output format examples
- Add docs/writing.md covering create-table, upsert, update, delete, drop
- Update docs/queries.md with output format options (--csv, --tsv, --nl, --table)
- Update docs/inserting.md with cross-references to upsert/update
- Update docs/index.md toctree to include new pages
- Regenerate all cog --help blocks with current command signatures

https://claude.ai/code/session_01DoiJf9Gbvbw2asN9yvP6dx

docs/inserting.md

@@ -4,6 +4,8 @@ The `dclient insert` command can be used to insert data from a local file direct
 
 First you'll need to {ref}`authenticate <authentication>` with the instance.
 
+See also {doc}`writing` for related commands: `upsert`, `update`, `delete`, `drop`, and `create-table`.
+
 To insert data from a `data.csv` file into a table called `my_table`, creating that table if it does not exist:
 
 ```bash
@@ -138,3 +140,7 @@ Options:
 
 ```
 <!-- [[[end]]] -->
+
+:::{note}
+To update existing rows rather than inserting new ones, see {doc}`writing` for the `upsert` and `update` commands.
+:::