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.

CONTRIBUTING.md

@@ -1,7 +1,21 @@
 # Contributing to Ashvale Station
 
-Thanks for taking an interest. This is a small project maintained by one person,
-so the bar here is "make it easy to say yes", not "follow a 40-page process".
+Read this first, so nobody wastes an afternoon.
+
+**This is a solo project.** It is written and maintained by one person, for one
+weather station, and it is published because the methods may be useful to
+someone else, not because it is looking for a team.
+
+**Bug reports are genuinely welcome.** If something crashes, forecasts badly, or
+the documentation is wrong, open an issue. That is useful and I will read it.
+
+**Pull requests are unlikely to be merged.** Not from lack of gratitude: this
+codebase carries a lot of hard-won reasoning in its comments and docstrings, and
+reviewing changes to it properly costs more time than I have. If you want it to
+do something different, fork it. Apache 2.0 exists precisely so you can.
+
+The rest of this file documents how the project holds itself to a standard. It
+is written for anyone reading the code, including future me.
 
 ## Ground rules that actually matter
 
@@ -54,7 +68,10 @@ python run.py --no-led                        # dashboard on :8000
 No Sense HAT needed. The simulator kicks in automatically and exercises every
 code path.
 
-## Before you open a pull request
+## The bar any change has to clear
+
+Whether it is my own commit or a fork of yours, a change to the forecasting
+path is not finished until it can show:
 
 - [ ] `python scripts/evaluate.py` runs clean, and you have posted before/after numbers
 - [ ] Those numbers came from a backfill with `--seed` and `--end` both pinned
@@ -63,16 +80,18 @@ code path.
 - [ ] New model code explains its failure mode in the docstring
 - [ ] The dashboard still fits one viewport at 1280x800 if you changed the UI
 
-## Good first contributions
+## Roadmap
+
+Where this is going, in rough order of value. Listed so a forker knows what is
+already planned rather than as an invitation.
 
 - **DS18B20 or BME280 support.** An outdoor sensor removes the single biggest
   limitation in the project. High impact, self-contained.
 - **Tipping-bucket rain gauge on GPIO.** Real precipitation labels would
   transform the precipitation model.
 - **METAR ingestion** from a nearby airfield as a calibration reference.
-- **Translations** for the dashboard.
 - **Tests.** There is a walk-forward backtest but no unit test suite. A pytest
-  suite over `physics.py`, `estimation.py` and `models/rls.py` would be very welcome.
+  suite over `physics.py`, `estimation.py` and `models/rls.py` is the main gap.
 
 ## Reporting bugs
 
@@ -81,8 +100,8 @@ output of `GET /api/status`, and what you expected instead. If it is a
 forecasting problem rather than a crash, the output of `scripts/evaluate.py`
 helps enormously.
 
-## Licensing of contributions
+## Licensing
 
-By contributing you agree that your work is licensed under the Apache License
-2.0, the same terms as the project. You keep the copyright in your own
-contributions.
+The project is Apache 2.0. Fork it, modify it, ship it, subject to the licence
+terms. In the unlikely event a patch is accepted, it is taken under the same
+terms and you keep the copyright in your own work.