fix(web): hide resource subscription UI when server lacks subscribe capability (#1479)

* fix(web): hide resource subscription UI when server lacks subscribe capability (#1478)

Thread a `subscriptionsSupported` flag derived from
`capabilities?.resources?.subscribe === true` from App through
InspectorView → ResourcesScreen to the leaf components. When false:

- ResourcePreviewPanel hides the Subscribe/Unsubscribe button (Refresh
  stays).
- ResourceControls omits the Subscriptions accordion section entirely,
  dropping it from `allSections` so the expand/collapse-all toggle and
  open-section bookkeeping stay correct even if a stale "subscriptions"
  entry persists from a prior subscription-capable session.

The flag defaults to true at the leaf components so existing callers,
tests, and stories keep rendering the subscription controls unless a
server is explicitly marked unsupported.

Adds unit tests and Storybook stories covering the hidden and shown
states across all three components.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* fix(web): give the Servers screen scroll the same gutter/idle-hidden treatment (#1474)

The server grid's ScrollArea.Autosize used the default type="hover" with no
offsetScrollbars, so the scrollbar popped in on hover and overlaid the right
edge of the server cards (occluding their action icons / status badges) — the
same problem #1474 fixed for the History/Network/Logging list panels.

Apply the same `type="scroll"` + `offsetScrollbars` treatment, and reuse the
shared `expectScrollbarGutterIdleHidden` story assertion to regression-protect
the gutter + idle-hidden behavior.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* fix(web): stop the InspectorView shell from scrolling as a whole

AppShell.Main carried Mantine's default `padding="md"` on top of the
fixed-header offset, but every screen already sizes itself to
`calc(100vh - header)` and supplies its own `xl` padding (with no
allowance for Main's padding). That extra inset pushed screen content
past the viewport, so the whole InspectorView gained a page-level
scrollbar instead of confining overflow to each screen's inner
ScrollArea.

Set the shell `padding` to 0 (Main now contributes only the header
offset, matching what the screens were built for) and clamp the Main
slot to `height: 100dvh` with `overflow: hidden` in the theme, so the
view can never scroll regardless of content — only the inner ScrollArea
regions do.

Adds an InspectorView story play assertion guarding the invariant
(Main clips + is viewport-clamped) and a ManyServers fixture that
confirms it holds under enough content to overflow, with the inner
server-grid ScrollArea absorbing the overflow.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* fix(web): address review — align viewport units + drop stale subscriptions intent

Responding to the @claude review on #1479:

- Align all screen height calcs from `100vh` to `100dvh` so they match the
  Main slot's `100dvh` clamp. On a mobile viewport where `dvh < vh` a `100vh`
  child would have exceeded Main's `100dvh` content box and been clipped by
  `overflow: hidden`; the units are now in lockstep.
- Restrict `intendedButEmptySections` in ResourceControls to `allSections` so a
  stale "subscriptions" entry persisted from a prior subscription-capable
  session is dropped from persisted open-sections instead of being perpetually
  re-appended once the section is no longer rendered. Adds a regression test.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

clients/web/src/App.tsx

@@ -2316,6 +2316,7 @@ function App() {
         onRefreshResources={onRefreshResources}
         onCompleteArgument={onCompleteArgument}
         completionsSupported={capabilities?.completions !== undefined}
+        subscriptionsSupported={capabilities?.resources?.subscribe === true}
         onTasksUiChange={setTasksUi}
         onCancelTask={(taskId) => {
           void onCancelTask(taskId);