feat: add Atlas native app UX overhaul

Docs/Execution/Week-03.md

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+# Week 3 Plan
+
+## Goal
+
+Freeze architecture, protocol, worker/helper boundaries, and scaffold inputs.
+
+## Must Deliver
+
+- `Architecture v1`
+- `Protocol Schema v1`
+- `Task State Machine v1`
+- `Error Registry v1`
+- `Worker XPC` interface
+- `Privileged Helper` action allowlist
+- Package and target dependency graph
+
+## Day Plan
+
+- `Day 1` Confirm minimum data required by the three core screens
+- `Day 2` Freeze schema, state machine, error mapping
+- `Day 3` Freeze worker/helper interfaces and validations
+- `Day 4` Freeze scaffold structure and dependency graph
+- `Day 5` Gate review for Week 4 engineering start
+
+## Owner Tasks
+
+- `Core Agent` freeze protocol, state, persistence
+- `System Agent` freeze worker/helper interfaces
+- `Mac App Agent` freeze shell and package graph
+- `Adapter Agent` freeze MVP adapter paths
+- `QA Agent` define contract and boundary test coverage
+
+## Exit Criteria
+
+- Week 4 can start implementation without unresolved P0 architecture blockers