Add wide view and inline editing to Measurements page

The Measurements page gains a compact/wide view toggle (persisted in
localStorage). The wide view is a pivot table: rows = time points,
columns = quantity names (alphabetical), cells = value + delete button.

Clicking a value in either view opens an inline edit panel (Turbo Stream)
without leaving the page. The panel shows the quantity name, value input,
unit selector, taken_at picker, and Update/Cancel buttons.

Changes:
- MeasurementsController: add edit/update actions; order by taken_at desc
- measurements/index: compact table + wide container, view-toggle buttons
- measurements/_readout: data-* attributes for JS pivot builder; edit link
- measurements/_edit_panel, _edit_form, _edit_form_close,
  edit.turbo_stream, update.turbo_stream: inline edit views
- application.js: groupMeasurements, buildWideTable (alphabetical cols),
  getMeasurementsView / setMeasurementsView, editMeasurementWide,
  readoutUnitChanged, setDefaultUnit
- application.css: compact/wide visibility rules, .wide-cell flex layout,
  button.link reset, .items-table .form td alignment
- Pictograms: view-rows.svg, view-columns.svg (view-toggle icons)
- Locale: view_compact/view_wide toggle labels, edit link, update.success
- Tests: system tests for compact inline edit and wide view edit panel

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

test/system/measurements_test.rb

@@ -0,0 +1,64 @@
+require "application_system_test_case"
+
+class MeasurementsTest < ApplicationSystemTestCase
+  setup do
+    @user = sign_in(user: users(:alice))
+
+    @quantity = @user.quantities.create!(name: 'Weight')
+    @unit = @user.units.create!(symbol: 'kg')
+    @readout = @user.readouts.create!(quantity: @quantity, unit: @unit, value: 82.5)
+
+    visit measurements_path
+  end
+
+  test "index shows quantity name as edit link for active user" do
+    within 'tbody' do
+      assert_selector :link, exact_text: @quantity.name
+    end
+  end
+
+  test "edit opens inline form on quantity link click" do
+    within 'tbody' do
+      click_on @quantity.name
+      assert_selector ':focus'
+      assert_selector 'input[name="readout[value]"]'
+    end
+  end
+
+  test "edit and update measurement value" do
+    within 'tbody' do
+      click_on @quantity.name
+      fill_in 'readout[value]', with: '83.1'
+      assert_difference ->{ @readout.reload.value }, 83.1 - @readout.value do
+        click_on t('helpers.submit.update')
+      end
+      assert_no_selector :fillable_field
+      assert_selector :link, exact_text: @quantity.name
+    end
+    assert_selector '.flash.notice', text: t('measurements.update.success')
+  end
+
+  test "cancel edit restores original row" do
+    within 'tbody' do
+      click_on @quantity.name
+      assert_selector 'input[name="readout[value]"]'
+      click_on t(:cancel)
+      assert_no_selector :fillable_field
+      assert_selector :link, exact_text: @quantity.name
+    end
+  end
+
+  test "wide view edit opens panel form" do
+    @readout.update!(taken_at: Time.now)
+    visit measurements_path
+    execute_script("localStorage.removeItem('measurements-view')")
+    visit measurements_path
+
+    find('button[data-view="wide"]').click
+    within '#measurements-wide' do
+      assert_text format("%.10g", 82.5), wait: 3
+      find('button.link').click
+    end
+    assert_selector '#measurement_edit_form input[name="readout[value]"]', wait: 5
+  end
+end