refactor: rename teacher/student to optimizer/target, remove best skills, fix slow update

- Rename teacher -> optimizer, student -> target across all code, configs, docs, prompts
- CLI: --teacher_model -> --optimizer_model, --student_model -> --target_model
- Remove best_skill files, keep only initial skills
- Fix slow update gate (force write into skill)
- Fix SLOW_UPDATE marker stripping
- Remove deep_reflect and meta_reflect mechanisms
- Update .env.example with export prefix and azure_cli docs
- Add endpoint empty validation in azure_openai.py

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

scripts/run_spreadsheetbench.sh

@@ -1,46 +1,37 @@
 #!/usr/bin/env bash
 # ──────────────────────────────────────────────────────────────────────────────
-# ReflACT — SpreadsheetBench training launch script
+# SkillOpt — SpreadsheetBench training launch script
 #
 # Usage:
-#   bash scripts/run_spreadsheetbench.sh \
-#       --data_root /path/to/data \
-#       --jsonl_path /path/to/benchmark.jsonl
-#
-#   bash scripts/run_spreadsheetbench.sh \
-#       --data_root /path/to/data \
-#       --jsonl_path /path/to/benchmark.jsonl \
-#       --num_epochs 2 --edit_budget 6
+#   bash scripts/run_spreadsheetbench.sh --split_dir /path/to/split --data_root /path/to/data
+#   bash scripts/run_spreadsheetbench.sh --num_epochs 2 --edit_budget 6
 # ──────────────────────────────────────────────────────────────────────────────
 set -euo pipefail
 
-# ── Paths ────────────────────────────────────────────────────────────────────
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
 PROJECT_ROOT="$(dirname "${SCRIPT_DIR}")"
 
-# Ensure ReflACT is importable
 export PYTHONPATH="${PROJECT_ROOT}:${PYTHONPATH:-}"
 
-# ── Model configuration ─────────────────────────────────────────────────────
-export TEACHER_DEPLOYMENT="${TEACHER_DEPLOYMENT:-gpt-5.5}"
-export STUDENT_DEPLOYMENT="${STUDENT_DEPLOYMENT:-gpt-5.5}"
+OPTIMIZER_MODEL="${OPTIMIZER_MODEL:-gpt-5.5}"
+TARGET_MODEL="${TARGET_MODEL:-gpt-5.5}"
 
-# ── Output directory ─────────────────────────────────────────────────────────
 TIMESTAMP=$(date +%Y%m%d_%H%M%S)
-DEFAULT_OUT_ROOT="${PROJECT_ROOT}/outputs/skillopt_spreadsheetbench_${STUDENT_DEPLOYMENT}_${TIMESTAMP}"
+DEFAULT_OUT_ROOT="${PROJECT_ROOT}/outputs/skillopt_spreadsheetbench_${TARGET_MODEL}_${TIMESTAMP}"
 
-# ── Run ──────────────────────────────────────────────────────────────────────
 echo "============================================================"
-echo "  ReflACT — Reflective Agent Tuning (SpreadsheetBench)"
+echo "  SkillOpt — SpreadsheetBench Training"
 echo "============================================================"
-echo "  Teacher:  ${TEACHER_DEPLOYMENT}"
-echo "  Student:  ${STUDENT_DEPLOYMENT}"
+echo "  Optimizer:  ${OPTIMIZER_MODEL}"
+echo "  Target:  ${TARGET_MODEL}"
 echo "============================================================"
 
 cd "${PROJECT_ROOT}"
 
 python scripts/train.py \
-    --config configs/spreadsheetbench_default.yaml \
+    --config configs/spreadsheetbench/default.yaml \
+    --optimizer_model "${OPTIMIZER_MODEL}" \
+    --target_model "${TARGET_MODEL}" \
     --out_root "${DEFAULT_OUT_ROOT}" \
     "$@"