fix(viewer): repair broken commands and references in the skills

[Fluzko]

Closes #913. Stacked on #979, which removes the HTML report skill.

Problem

Several things the skills and docs tell a reader to do don't work for someone who got the skills through Symposium:

• The README and a design doc name skills that don't exist (recipes, analysis).
• The zoom-window skill sends the reader to dial9-viewer/ui/README.md for the list of viewer URL parameters, and tells them not to invent any. That file doesn't ship with the skills or with any crate, so the list can't be reached.
• dial9 agents tells the reader to run dial9-viewer agents ..., even when they only installed dial9.
• The S3 skill says the toolkit runs on Node.js 14 or newer; it needs 16.
• A toolkit script mentions a command that doesn't exist (dial9-viewer agents analyze).

What this PR does

• Fixes the skill names in the README and the design doc.
• Moves the list of viewer URL parameters out of the UI README into its own file, and ships that file with the zoom-window skill through a symlink, the same way the toolkit already ships the viewer's trace parser. There is still one copy, and the existing contract tests now check that file against the code. The UI README keeps the notes for maintainers.
• dial9 agents now prints its commands with the name of the binary you actually ran.
• Corrects the Node.js requirement (the toolkit was run on Node 16, 18 and 25 with identical output) and removes the stale command from the script.

How it was checked

• New test: the agents overview names the binary it was run as.
• The URL contract tests pass against the new file, along with the rest of the UI tests and cargo nextest run.
• Both packaged crates carry the URL parameter list as a regular file, identical to the source.