fix(web,harness): the demo's second view was the phantom improvise-m4rv removed

CROSSES TWO BOUNDARIES OUTSIDE THIS AGENT'S GROUND, deliberately and reported:
web/demo.improv and harness/tests/contract.spec.js. Dropping the invented
Default view takes the shipped demo from two views to one, and the spec
asserted the phantom in two places -- improvise-m4rv's acceptance criteria
name the spec directly.

The load-bearing half is the improvise-iioi click test, which needs the view
panel to hold two rows so that a click can name a DIFFERENT row than the
cursor does; with one view both readings give the same answer and the test
stops discriminating. The phantom was supplying that second row by accident.

So the demo gains a real second view, Season -- a genuine alternate pivot
(Quarter by measure, paged by Product) rather than an auto-arrangement. Plan
stays first and stays Initial View, so the cursor still starts at index 0 and
tests/web_demo_model.rs is unaffected: every visible cell of the ACTIVE view
is still a Record (gotcha 46). Verified by cargo.

The spec's axis assertion at index 0 moves from the phantom's "R:Product
C:Quarter" to Plan's own "R:Product P:Quarter", derived from
viewmodel::view_axis_summary rather than guessed.

NOT VERIFIED: harness/ has no node_modules and web/pkg is unbuilt here, so
Playwright could not be run. These edits are mechanical substitutions and
need a browser-job run before they are believed.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FC2jVn8Au7E9JPkw6bwXXH

web/demo.improv

@@ -10,6 +10,14 @@ _Index: none
 _Dim: none
 format: ,.0
 
+## View: Season
+Quarter: row
+_Measure: column
+Product: page, Latte
+_Index: none
+_Dim: none
+format: ,.0
+
 ## Formulas
 - Profit = Revenue - Cost