fix(tasks-ui): postmodern chrome, working clicks, adaptive layout, lean cards

Review feedback from the live 3384 install, fixed at the root:

- COLORS: the new stylesheet used var(--dsw-alias-accent) in 17 places — a
  token the DSH theme does NOT define, so every declaration was dropped
  (older files only survived because they carry fallbacks); container edges
  used border-l1 (4% black, invisible). Accent now rides
  --dsw-alias-state-business-primary, container edges --dsw-alias-border-l4.
- CLICKS: the canvas called setPointerCapture on pointerdown, which
  retargets the derived click to the container and killed every node (and
  ⓘ) interaction; jsdom cannot see this, a real browser can. Capture is
  gone and panning only starts from the background.
- LAYOUT: fit gave up silently at zero container size and never retried,
  centered only horizontally, and capped at 100% while a five-child level
  scaled to 35%. Now: ResizeObserver + first non-zero fit, both axes
  centered, a 0.78 readability floor, and layoutTasksGraphForWidth picks
  the flattest sibling arrangement that still meets that floor.
- CARDS: title (one line) + mono meta + live line only; display title,
  team role, full model id and latest text moved into the ⓘ popover.
- PANEL: metrics follow the approved 360x660 mockup (132x46 cards, 112 row
  stride), explicit line-heights, user-select:none, horizontal control
  cluster with a labelled mode button, always-visible team board strip.
- Tokens for two new popover headings across all 20 dictionaries.

Tests: 3 new page-interaction specs (click after background pointerdown,
node gestures never pan, team board visible without a click) and a
rewritten 9-case layout suite (band wrap, row reservation, width solver,
reserved live row). Full suite 1400 passed / 133 files.

src/client/SubagentView.module.css

@@ -9,20 +9,24 @@
   flex-direction: column;
 }
 
+/* The page header keeps the mockup's rhythm: a 13px semibold title, a mono
+   count, and a hairline underline that separates chrome from content. */
 .subagentHeader {
   flex: none;
   display: flex;
-  align-items: center;
+  align-items: baseline;
   gap: 8px;
-  height: 36px;
-  padding: 0 8px 0 12px;
+  padding: 10px 10px 9px 12px;
+  border-bottom: 1px solid var(--dsw-alias-border-l4);
 }
 
 .subagentTitle {
   flex: 1;
   min-width: 0;
-  font: var(--dsw-font-s-14);
-  color: var(--dsw-alias-label-secondary);
+  font-size: 13px;
+  line-height: 1.35;
+  font-weight: 600;
+  color: var(--dsw-alias-label-primary);
   overflow: hidden;
   text-overflow: ellipsis;
   white-space: nowrap;
@@ -31,8 +35,9 @@
 /* The descendant count badge ("3 · 1 运行中") beside the title. */
 .subagentCount {
   flex: none;
-  font: var(--dsw-font-xxxs-11);
-  color: var(--dsw-alias-label-tertiary);
+  font-family: var(--ds-font-family-code);
+  font-size: 10px;
+  color: var(--dsw-alias-label-secondary);
 }
 
 .subagentRefresh {
@@ -40,16 +45,18 @@
   display: inline-flex;
   align-items: center;
   justify-content: center;
-  width: 24px;
-  height: 24px;
+  width: 20px;
+  height: 20px;
+  padding: 0;
   border: none;
-  border-radius: 6px;
+  border-radius: 3px;
   background: transparent;
-  color: var(--dsw-alias-label-secondary);
+  color: var(--dsw-alias-label-tertiary);
   cursor: pointer;
 }
 
 .subagentRefresh:hover {
+  color: var(--dsw-alias-label-primary);
   background: var(--dsw-alias-interactive-bg-hover);
 }