Feature request: open a notebook with all cells not auto-running, but wait viewers to click run each cell on-demand?

[tx0c]

Is your feature request related to a problem? Please describe.
when using Observable with databases, some queries are expensive, so as an editor, I don't want all my future viewers to see all cells running and pending when opening the page, it can take a long while and it's frustrating, sometimes overload the DB server and failing some queries,

Describe the solution you'd like
I want editor has a control to say: all DB cells started with a stop state, then only when viewer click a button to reveal results, only query that specific cell under viewer's request

Describe alternatives you've considered
https://talk.observablehq.com/t/how-to-disable-automatic-execution/3981 mentioned "disable automatic execution" and I am aware /safe mode, but safe mode cannot run any cells and is only editor debugging purpose, not for viewers;

Additional context
To Be Filled under request.

[tx0c]

request again for #336 , to change the names of a cell should not trigger re-run; some DB cells are very expensive, that feature is for editors editing;
now for better presenting to viewers, want finer control of

1. what DB cells to run,
2. what time to run, and
3. how many to run concurrently;

would like a setting of how many concurrency at each DB level? e.g. only 5 concurrent queries at same time? for a typical notebook with 30 ~ 60 DB cells, don't want all DB cells to query the server at same time of viewers' opening the notebook, those should be running in a ConcurrencyRateLimitQueue

[tomlarkworthy]

Strongly disagree and you can create manually runnable cell with your own buttons easily