Studio: unified web UI for agent monitoring, memory, notes, and tasks

Unify the scattered web UIs and agent management interfaces into a single cohesive Studio.

Current state (fragmented):

• task web - task dashboard (still branded as "jr", needs refresh)
• Omni/Agentd/Studio.hs - experimental agent creation UI (failed experiment)
• Omni/Agent/Memory.hs - memory DB with only Haskell API
• Omni/Agent/Tools/Notes.hs - notes DB with only Haskell API
• agentd - agent container runtime (CLI only)

Unified Studio vision: agentd studio (or just studio) should be a single web UI for: 1. Agent monitoring - watch running agents, view logs/events (NOT creating agents - that's for a 'foreman' agent) 2. Memory browser - search, inspect, delete stale memories, visualize connections 3. Notes browser - search, manage notes by user/topic 4. Task dashboard - absorb/replace task web functionality, remove "jr" branding

Implementation:

• Consolidate into Omni/Agentd/Studio.hs
• Reuse patterns from Omni/Task/Web/ (Components, Handlers, Pages, Style)
• Use DevBrowser tool to test the UI end-to-end

Supersedes t-442.