Build an evidence-first dashboard Shift Brief

[FZ2000]

Effect in one sentence

Turns the Dashboard into an evidence-first Shift Brief: one server-ranked review item, its recorded reason/next step, and a direct path to the underlying evidence.

Stack position

2 of 6: #153 → #155 (this Shift Brief) → #157 → #159 → #160 → #161.

This branch is based on #153, not main; the stack is an alternative to standalone #152.

State contract

Attention state	Presentation
Loading	Checking recorded work; no clear claim
Current endpoint error	Review status unavailable, even if old success is retained
Authoritative total zero	No recorded work needs review
Positive total and valid row	Leading Task, recorded reason/time/provenance/next step, Review evidence
Positive total with malformed/missing row	Review details unavailable

What changes

• Loads the dedicated attention endpoint on an independent refresh lane.
• Promotes one server-ranked Task and keeps evidence review primary.
• Adds a bounded queue route into Work while preserving the exact complete count.
• Recasts activity, capacity, ingestion trust, Recent Work, and usage as supporting signals.
• Keeps provider allowance, usage/cost, active work, and ingestion health independent.

Review order

1. Swift models/store and error precedence.
2. Shift Brief hierarchy and routing.
3. Work Attention queue.
4. Interaction/harness tests and six Dashboard references.

Verification at current head 734e08b

• Current-head GitHub CI passes pytest on Python 3.11/3.12/3.13 and the macOS app/snapshot job.
• Dashboard interaction tests — 18 passed.
• Dashboard snapshot harness — 6 passed.
• Canonical Dashboard verification — all six references match.
• All six light/dark minimum/reference/unavailable images were manually inspected.
• git diff --check against Add a bounded dashboard attention projection #153 — clean.

Scope

No provider, agent, or Task mutation is added. Copying a brief remains isolated in #157.