The floating button's `settledLevel` has been unused since the working animation changed, but Docs/app-dock.md and a comment still describe the settle

## What happens

- `Sources/Uttrflow/Dock/DockView.swift:509` declares `static let settledLevel: CGFloat = 0.18`, "Where the row settles when the microphone closes". Nothing reads it: `git grep -w settledLevel -- Sources Tests` finds only the declaration. Its one use was removed in eb4db2e ("Say one thing while working, and end it with a tick"), which replaced the settling row with three walking dots.
- `Docs/app-dock.md:32-33` still says "`settledLevel` 0.18 is where the row settles when the microphone closes; zero reads as a broken panel."
- `DockView.swift:372`, the doc comment on `WorkingDots`, says "Working: the row settles level and folds to a tick, once, and stops scrolling", which is what the struct used to do. The struct now draws three dots that pulse for as long as work is left (`Docs/app-dock.md:34-38` describes that correctly).

## Why it matters

Someone changing the button's animation reads the constant and the comment, and looks for a settle that no longer exists.

## Acceptance criteria

- `settledLevel` is removed.
- The sentence about it in `Docs/app-dock.md` is removed.
- The `WorkingDots` doc comment describes the dots.
- `make verify` passes (`make docs-audit` and `make comment-audit` cover the doc and the comment).

## Where to start

- `Sources/Uttrflow/Dock/DockView.swift` lines 372 and 509, `Docs/app-dock.md` line 32.
- Read [CONTRIBUTING.md](https://github.com/uttrflow/uttrflow-swift/blob/main/CONTRIBUTING.md) first, and say on this issue that you are taking it.
- Before pushing, run `make verify` (with `DEVELOPER_DIR` pointing at Xcode 26.6 or later). It is the same command CI runs.

**Size:** XS, under 30 minutes.

Read CONTRIBUTING.md first, then inspect Sources/Uttrflow/Dock/DockView.swift at the WorkingDots comment and settledLevel declaration, plus Docs/app-dock.md around line 32. Remove the obsolete constant and descriptions, update the comment to describe the pulsing dots, and run make verify with the required Xcode version; done means the documented audits and verification pass.

Written by the indexing model from the issue text.