Merge Forecast into Live, four tabs; state solo-project policy

The Live tab now carries the observed-and-forecast chart (a superset of the
old rolling window, which plotted the same observed series without the
prediction) and the precipitation panel. Estimator internals moves to Models,
beside the calibration input that sets the coefficient it reports. The seven
day outlook moves to History. Verified in Chromium at 1600x900: all four tabs
scrollHeight 900 against innerHeight 900, zero clipped elements outside
internal scrollers, zero console errors.

CONTRIBUTING.md now states plainly that this is a solo project: bug reports
welcome, pull requests unlikely to be merged, fork it instead. No other
developer was ever named anywhere in the repository.

README.md

@@ -160,18 +160,21 @@ permanently.
 
 ## The dashboard
 
-Five tabs, one viewport, no scrolling on desktop. Below 1024 px the constraint is
-released, because pinning five panels into a phone viewport produces unreadable
+Four tabs, one viewport, no scrolling on desktop. Below 1024 px the constraint is
+released, because pinning four panels into a phone viewport produces unreadable
 eight-pixel type.
 
 | Tab | Answers |
 | --- | --- |
-| **Live** | What is it doing right now |
-| **Forecast** | What is it about to do, and how sure are we |
+| **Live** | What is it doing now, what it expects next, and how sure it is |
 | **History** | What did it do, over any timeframe you ask for |
 | **Models** | Has the model earned its confidence |
 | **Methods** | How the whole thing is wired, and how each stage fails |
 
+Live carries the current readings, the observed-and-forecast chart with its 90%
+conformal band, and the precipitation panel together, so the question "what is
+it doing and what happens next" is answered without changing tab.
+
 ### History
 
 Presets from 6 hours to a year, plus an explicit from/to range picker. Aggregation