tool timeline in sidebar + compact chat tools + scroll fixes

- SessionDigest now includes live tool timeline, plan steps, knowledge
- ToolCallGroup compact: single-line with collapsible names only (no JSON)
- Activity bar moved to bottom of messages, smart scroll respects user position
- setGoal now sets status=executing (removed stuck planning state)
- PlanProgress merged into SessionDigest, removed from TaskContextPanel
- New toolTimeline derived store in chat.ts

web/src/lib/components/TaskContextPanel.svelte

@@ -2,7 +2,6 @@
   import { onMount } from 'svelte'
   import { startWorkspace } from '$lib/stores/workspace'
   import GoalHeader from './GoalHeader.svelte'
-  import PlanProgress from './PlanProgress.svelte'
   import OperatorQuestion from './OperatorQuestion.svelte'
   import SessionGraph from './SessionGraph.svelte'
   import SessionDigest from './SessionDigest.svelte'
@@ -20,7 +19,6 @@
 -->
 <div class="flex h-full min-h-0 flex-col">
   <GoalHeader />
-  <PlanProgress />
   <OperatorQuestion />
   <div class="min-h-0 flex-1">
     <SessionGraph />