v2.2.3 — the Approvals tab, the scale row, and a scrape with rates

Added

• An Approvals tab in Metrics: how many actions the gate held for a person, how many they
  answered, how many they refused, how many expired, and the median time to answer — the
  number that says whether the gate is working rather than merely running. A person's refusal is
  counted apart from a policy refusal nobody was asked about, because merging them overstated the
  approver's denials sixteen-fold on the deployment this was measured against. An ask that was
  neither answered nor expired is named on its own: nothing ran and nothing said why.
  (#274)
• A scale row at the top of Metrics → Usage: servers, skills, agents, MCP servers and connectors,
  in one request. Every one of these existed and was scattered across five settings pages. A
  count that cannot be read shows — and names itself rather than reading as zero.
  (#274)
• /metrics exports counters and a latency histogram, so a Prometheus install can ask for a rate
  and a quantile rather than only a level: nanoinfra_llm_calls_total,
  nanoinfra_llm_tokens_total (by input, output, cache read and cache write),
  nanoinfra_tool_calls_total, and nanoinfra_llm_duration_ms over nine buckets. Accumulated in
  memory for the life of the process, because a count over a table with a purge is not monotonic
  and a rate() over a falling counter is nonsense.
  (#274)
• Two process-health gauges, nanoinfra_rss_bytes and nanoinfra_event_loop_lag_ms. A rising lag
  is a blocked loop, and neither number has an event to be driven by, so both are sampled at read.
  (#274)

Fixed

• The gate audit viewer no longer offers deny as a decision filter. Nothing writes it: the name
  lives on as the outcome enum and as the operator socket's wire verb, and the log records that
  outcome as denied so it speaks the operator's vocabulary. The filter could only ever match
  zero records. (#274)