feat(tasks): phase 6 — live TaskContextPanel (goal, plan, question, entities)

Replaces the chat right rail's ad-hoc Digest+Graph stack with a single
TaskContextPanel that renders the task's live working state, driven by the
always-on events stream (not the per-turn chat SSE) so it keeps updating
during server-side auto-continuation/resume:

- GoalHeader: goal + status pill (planning/executing/awaiting_input/done/
  failed), sourced from the sessions list.
- PlanProgress: ordered steps with live status icons + progress bar, hydrated
  via new GET /sessions/{id}/plan; clicking a step with a target opens its
  EntitySheet (no fake "jump to transcript" — bits-ui Collapsible content
  isn't force-mounted, so a DOM-scroll jump would silently no-op for
  collapsed tool groups).
- OperatorQuestion: the pinned structured question card (prompt/why/entity
  chips/option buttons/free-text), hydrated via new GET /sessions/{id}/
  questions; answering POSTs to the existing answer endpoint.
- SessionGraph upgraded to a live entity panel: entity.touched pulses the
  node (animated ring) and shows "Now touching <slug>"; health.changed shows
  a transient diff badge for touched entities.
- SessionDigest gains a success/failure/partial outcome banner and now also
  refetches when the task's status changes, not just on session switch.

Two bugs found and fixed while wiring this up:
- workspace.ts's status-refresh trigger only covered goal.set/task.status;
  question.raised/answered didn't refresh the sessions list, so GoalHeader's
  pill went stale after answering via the panel (resumeSession runs entirely
  server-side — no client 'done' event to piggyback a refresh on). Now every
  status-affecting event triggers the (debounced) refetch.
- Forgot to rebuild the nomos container after adding the /plan and
  /questions endpoints, so they silently fell through to the old default GET
  handler — caught via a live curl diff against the running container,
  not a code read.

Verified end-to-end against the live stack: goal/plan/question all update
without a reload as the agent works; answering a question via the panel
resumes the agent and the header pill correctly flips to Executing;
entity.touched pulses the live graph.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

web/src/pages/Chat.svelte

@@ -1,8 +1,7 @@
 <script lang="ts">
   import { messages, streaming, sendMessage, cancelStream, error } from '$lib/stores/chat'
   import SessionRail from '$lib/components/SessionRail.svelte'
-  import SessionGraph from '$lib/components/SessionGraph.svelte'
-  import SessionDigest from '$lib/components/SessionDigest.svelte'
+  import TaskContextPanel from '$lib/components/TaskContextPanel.svelte'
   import ToolCallGroup from '$lib/components/ToolCallGroup.svelte'
   import InlineApproval from '$lib/components/InlineApproval.svelte'
   import { Button } from '$lib/components/ui/button'
@@ -181,7 +180,7 @@
         type="button"
         class="group/rz relative w-1.5 shrink-0 cursor-col-resize touch-none"
         onpointerdown={startResize}
-        aria-label="Resize session graph"
+        aria-label="Resize task panel"
       >
         <span
           class="absolute inset-y-0 left-1/2 w-px -translate-x-1/2 transition-colors {resizing
@@ -190,10 +189,7 @@
         ></span>
       </button>
       <div class="flex min-w-0 flex-1 flex-col">
-        <SessionDigest />
-        <div class="min-h-0 flex-1">
-          <SessionGraph />
-        </div>
+        <TaskContextPanel />
       </div>
     </div>
   {/if}