feat: Usage and Observability follow the scope filter

[pacphi]

Why

Usage ignores plain folders and reads user-level stores (design: Usage, Observability and telemetry).

In scope

Filter and host facet on every panel; Projects becomes Places; tool-family tags; derived state moves to the cache; Limits show where and when they were last sampled (D07).

Out of scope

Telemetry (#375).

Acceptance criteria

• Places rows add up to the totals
• Limits show their sample source and time
• On a corpus of about 1,000 sessions, no Usage or Observability panel reads as empty while its data loads, and a test loads each panel cold (D01, from the chore: triage D01, D10 and the [BLOCKED] hook exit-code finding #319 triage)

Dependencies

Blocked by: #366

Blocks: #375, #388

Plan

• Release: 4.0.0-beta.4
• Size: size:M · Workstream: ws:project-scope
• Epic: feat: project-scope P6, the dashboard for all work (epic) #301
• Card: P6-12 in the card inventory
• Sources: Design (docs(plans): project-scoped management design and its prerequisites #289) Usage, Observability and telemetry; v5 impact review (docs(plans): v4 GA master plan, supersession ledger and v5 registers #290) D07; A61-16 (chore: triage D01, D10 and the [BLOCKED] hook exit-code finding #319) D01 triage

Verification

• pnpm run test:ui