feat(dashboard): report qualified host health across all hosts

[pacphi]

What changes

Persistent host badges previously reported usage-parser degradation, so a historical Codex rollout could make a working host look unhealthy. Replace those badges with the same qualified health contract for Claude, Codex, and OpenCode: OK, Attention, Checking, Unknown, or Disabled.

• Click a badge to inspect local checks, project scope, selection, and timestamps. Keep transcript/database diagnostics in Usage.
• Add explicit, confirmed provider connection checks with bounded execution, restricted tools, fresh challenge responses, source-bound one-use confirmation, cancellation, and result expiry. Polling never invokes inference. MCP connectivity remains separately untested.
• Add real local OpenCode configuration/authentication assessment and capability-based native probes without exact-version locks.
• Amend ADR-0023/0053 and correct ADR-0051: its implementation was published in alpha.48.

Validation

• 77 focused health tests passed, including HTTP authorization, isolation overrides, native subprocess stdin, and process-tree timeout cleanup.
• Browser suite: 491 assertions plus 9 tests passed; final health dialog also verified on desktop/mobile.
• Legacy suites, typecheck, lint, complexity gate, Markdown lint, and build passed. Existing lint warnings remain.
• Live local checks returned OK for all three hosts. No paid inference was performed; connected checks use deterministic fixtures and intercepted native preflight.
• Local broad unit run: 4,159 passed, 6 existing skips, one existing stock OpenCode fixture timed out installing its npm SDK dependency before any provider request. The remote CI matrix subsequently passed.

GitHub validation at 3e8d46cf0eadd45bf4992f55d8b8296d90b755f3: all 15 applicable checks passed across the nine OS/Node combinations, minimum runtime, quality/audit, browser rendering, links, and maintainer devcontainer. The published-release consumer devcontainer was conditionally skipped.