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

agent/managed-skills/llm-fleet-model-swap/SKILL.md

@@ -37,5 +37,5 @@ Use when switching model, quant, or llama.cpp/FreeToken runtime for a `frank-def
 
 ## 6. Close-out (mandatory)
 - Docs: active runbook updated (build recipe, profile, validation numbers incl. real-workload prefill/decode), superseded runbook gets RETIRED banner kept as rollback record, `LLM/index.md` mermaid + active list, AGENTS.md fleet table + Runtime section + history chain, work log entry in `serverAppConfigs-docs/log.md`.
-- `~/.pi/agent/models.json`: contextWindow must equal the REAL per-slot context — llama.cpp logs `n_ctx_slot` per prompt; parallel N clamps `n_ctx_train` (e.g. 262144/2 = 131072/slot). Overselling causes silent client-side overflow.
+- `~/.omp/agent/models.yml`: contextWindow must equal the REAL per-slot context — llama.cpp logs `n_ctx_slot` per prompt; parallel N clamps `n_ctx_train` (e.g. 262144/2 = 131072/slot). Overselling causes silent client-side overflow.
 - Rollback = one env commit (paths + LLAMA_BIN); keep prior binary + payload on disk.