The flow vitals carry stranded spend, the oldest approved wait, and the red and queued counts, and home, the tick line and MCP `flow` show them #6424

Flow work for #5930. It joins the three reads into the one vitals reading, so home, the autonomy tick line and the MCP flow tool say the same numbers.

Done when:

• [ ] Vitals in src/flow/vitals.ts gains red, queued, oldestApprovedHours (null when none) and strandedUsd, filled by the three reads with the same publicOnly.
• [ ] vitalsMisses adds "oldest approved pull has waited N h" when it is over 24 h.
• [ ] Home's flow line, the tick line and MCP flow show the new numbers. Agents see strandedUsd only when they hold telemetry:read; otherwise the field is left out.
• [ ] Existing vitals tests are updated only where they asserted the exact shape; a new test covers the misses line and the field left out for an agent.

Files: src/flow/vitals.ts, its readers (src/actions/health.ts, the home page, the MCP flow tool's file), test/flow-vitals*.test.ts.