feat: Global agent activity timeline — aggregate memory events

[ajianaz]

What

Build a global activity timeline that aggregates memory events across all namespaces — giving users a bird's-eye view of what their agents are remembering, forgetting, and linking over time.

Why

Current timeline view (PR #218) is per-memory. Users need a global view to spot patterns: "My agent stored 50 memories today" or "No new memories in 3 days — is the agent offline?"

How

Data source

GET /recent is already covered in Corin (utekeServer.recent()). This issue uses that existing endpoint + aggregates by day/week.

Implementation

Layer 3 — ActivityTimeline.svelte:

• Vertical timeline with date headers
• Each day shows:
  • Memory count badge
  • Top 3 memories (preview, click to expand)
  • Type distribution mini-bar
• Filter by:
  • Namespace (all or specific)
  • Date range (last 7d, 30d, custom)
  • Memory type (fact, reference, etc.)
• Zoom levels: daily -> weekly -> monthly
• Activity heatmap (GitHub-style contribution graph) at top

Activity heatmap

  Jul                    Aug
  M T W T F S S    M T W T F S S
  . . . . . . .    . . . . . . .
  . . . . . . .    . . . . . . .
  . . . . . . .    . . . . . . .
  . . . . . . .    . . . . . . .
  . . . . . . .    . . . . . . .  <- today

• Green intensity = memory count that day
• Click day -> scroll timeline to that date

Integration

This is the third tab in the Agent Memory Dashboard:

1. Health Overview (stats)
2. Context Preview (POST /context)
3. Activity Timeline (this issue)

Testing

• Timeline renders with daily grouping
• Activity heatmap shows correct intensity
• Click heatmap day -> scrolls timeline
• Namespace filter works
• Date range filter works
• Type filter works
• Click memory -> opens detail
• Empty state: "No activity yet"

Related Issues

• Part of: Phase 3 — Agent Dashboard
• Builds on: PR feat(timeline): Integrate memory timeline endpoint end-to-end #218 (per-memory timeline)
• No new endpoints needed — uses existing /recent

Checklist

• ActivityTimeline.svelte
• Activity heatmap component
• Filters (namespace, date, type)
• Memory detail click-through
• Empty + loading states