[Umbrella] camp resource self-monitoring + self-protection

[rolker]

Goal

Give camp a single source of truth for its own resource footprint, use it to
protect itself from resource-exhaustion crashes (the salmon live-data crash,
#153), and report health via ROS diagnostics — with a lightweight status-bar
indicator for the operator riding on the same data.

Motivated by #153: camp crashed on the salmon operator station after enabling live
data because the live tile cache grows unbounded and exhausted memory/VRAM. camp
had no awareness of its own footprint and no way to shed load before crashing.

Design

One ResourceMonitor samples the process footprint and a self-accounted GPU-byte
counter (camp creates every texture itself, so it can total its own VRAM use
portably — the number that actually bounds the live cache). Everything else
consumes that snapshot: self-protection acts on it, ROS diagnostics report it, and
the status bar displays it.

Children

• ResourceMonitor core — self-sampled footprint + GPU-byte accounting #155 — ResourceMonitor core — sampling substrate + single source of truth
  (RSS, CPU%, threads, FDs via /proc/self; self-accounted GPU bytes; snapshot
  + change signal; no policy). Foundation — ships first.
• Resource self-protection + back-pressure (eviction budget, load-shedding, GUI watchdog) #156 — Self-protection / back-pressure — feed the live-cache eviction
  budget (Live tile cache is unbounded -> memory/VRAM exhaustion (crashed camp on salmon after enabling live data) #153), load-shedding guard near limits, GUI responsiveness watchdog.
• ROS diagnostics publisher for camp health + resource footprint #157 — ROS diagnostics publisher — diagnostic_msgs/DiagnosticArray +
  heartbeat from camp_map_ros; plugs into rqt_robot_monitor + deployment log.
• Status-bar operator resource/health indicator #158 — Status-bar operator indicator — addPermanentWidget gauge
  (RAM/VRAM/tiles + health dot), riding the same snapshot.
• Live coverage: bounded eviction + multi-resolution overview pyramid (consumer-side, fold-into-parent) #160 — live tile cache eviction + overview pyramid (unbounded → exhaustion;
  supersedes Live tile cache is unbounded -> memory/VRAM exhaustion (crashed camp on salmon after enabling live data) #153). Consumes the monitor's VRAM accounting as its eviction budget; the
  concrete first self-protection consumer, plus a consumer-side overview pyramid so
  zoom-out survives eviction.

Dependency order

#155 first (everyone needs the numbers) → then #156 (incl. #160), #157, #158
proceed in parallel against the snapshot.

Scope note

Self-protection + ROS diagnostics are the lead goals (operator UI is a thin rider,
not a separate effort). Distinct from the OGR/Georeferenced leak (#152), which is
the chart-load path and unrelated to resource monitoring.

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Authored-By: Claude Code Agent
Model: Claude Opus 4.8