v0.4.0

Added

• Maintain a fixed-capacity 15-minute history of completed ticks and one-second
  process/system CPU observations even when no profiler is running.
• Calculate independent 5-second, 10-second, 1-minute, 5-minute, and 15-minute TPS
  windows plus query-time MSPT distributions and rolling CPU usage.
• Populate profile metadata and per-second Viewer windows from the shared history,
  including exact time bounds, CPU, TPS, MSPT median/max, and low-cost player counts.
• Report real rolling TPS, MSPT distributions, and process/system CPU from
  /spark tps, with the available history duration shown during warm-up.

Changed

• Share one cross-platform process CPU normalization rule and keep allocation,
  sorting, and percentile work out of the per-tick statistics path.
• Omit unavailable per-second entity and chunk fields instead of copying a final
  world snapshot or serializing zero as though it were an observation.
• Make /spark health use the shared performance snapshot and consistently report
  available process RSS/virtual memory, threads, physical memory, swap/page-file,
  disk, uptime, players, CPU, and OS resources on Windows and Linux.
• Track resource-field availability explicitly and omit failed system/profile
  queries rather than presenting synthetic zero values.

Fixed

• Stop copying one TPS/CPU average across every rolling field or labeling MSPT
  means and maxima as median, minimum, and p95 values in profile metadata.
• Preserve the suspended thread's top instruction address on Windows when
  StackWalk64 cannot unwind a caller, instead of discarding the whole sample.
• Report reserved/committed process virtual address space on Windows instead of
  incorrectly labeling private commit charge as virtual memory.
• Retry Windows hook removal within the existing bounded shutdown interval when
  a concurrently starting or exiting thread temporarily rejects context capture.

Full Changelog: v0.3.2...v0.4.0