kb: retire pi-installation association (OMP is the primary harness)

Purge live-state claims that ~/.pi is our harness; keep general
pi documentation in omp-docs/ and dated historical records.

- README.md: single config source; Legacy Notes reworded
- AGENTS.md: drop 'like ~/.pi did' framing
- APPEND_SYSTEM.md: okf-spec -> omp-docs/references/okf-spec.md
- dotfiles/zsh/.zshrc: systemprompt alias -> APPEND_SYSTEM.md
- managed skill llm-fleet-model-swap + model_config_sync skill:
  single-source models.yml; validation script YAML-only
- memories (MEMORY.md, memory_summary.md, learned.md): single source
- omp-docs: .okf root -> ~/.omp/omp-docs; de-live pi-era claims in
  pi/index.md, pi-web-access.md, engineering/agents-files.md

dotfiles/zsh/.zshrc

@@ -30,7 +30,7 @@ export LD_LIBRARY_PATH="/opt/cuda/lib64:/home/dank/GitPackages/llama.cpp/build:$
 # GiTea
 
 # Terminal Aliases
-alias systemprompt="nvim ~/.pi/agent/SYSTEM.md"
+alias systemprompt="nvim ~/.omp/agent/APPEND_SYSTEM.md"
 
 # peon-ping quick controls
 alias peon="bash /home/dank/.claude/hooks/peon-ping/peon.sh"