Extract ourdigital-estimate-engine; presales-seo now calls it

New skill 96-ourdigital-estimate-engine: method-aware quoting engine
(effort / coaching / procurement) with universal rate_card + per-service
catalog. Real catalogs: seo (effort), education (coaching); stubs:
digital_ads, digital_branding. Validated to reproduce real quotes —
SEO basic ₩10.5M / treatment ₩25.0M, SHR chain ₩29.5M, L'Escape basic
₩10.5M, GA4/GTM coaching ₩1,570,000, procurement +15%.

Refactor 95-ourdigital-presales-seo: remove rate_card.yaml, sow_templates.yaml,
estimate.py (migrated to engine); add findings_to_scope.py; Stage 5 now maps
findings→scope.json and calls the engine CLI. build_deck/kg_query unchanged;
end-to-end validated on SHR (29.5M) + deck renders engine estimate.json.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

custom-skills/96-ourdigital-estimate-engine/scripts/methods/coaching.py

@@ -0,0 +1,61 @@
+"""Coaching method: cost = Σ(lesson_type_price × hours) over a lesson plan.
+
+Base lesson-type prices reproduce real quotes (GA4/GTM 중급 → ₩1,570,000).
+Optional matrix mode prices by subject level (base × level_multiple).
+Student-count discount is opt-in (real 1:1 quotes apply none).
+"""
+
+
+def _discount(rate, students, apply):
+    if not apply:
+        return 0.0
+    for mx, r in rate["coaching"]["student_discount"]["bands"]:
+        if students <= mx:
+            return float(r)
+    return 0.0  # 30+ → 별도 협의
+
+
+def _unit_price(rate, lesson, mode):
+    c = rate["coaching"]
+    base = c["lesson_type_prices"][lesson["type"]]
+    if mode == "matrix":
+        lvl = c.get("subject_levels", {}).get(lesson.get("subject"))
+        if lvl:
+            base = base * c["level_multiple"].get(lvl, 1.0)
+    return base
+
+
+def build(scope, rate, catalog):
+    c = rate["coaching"]
+    mode = scope.get("pricing_mode") or c.get("pricing_mode", "base")
+    if scope.get("lessons"):
+        lessons = scope["lessons"]
+        title = scope.get("course") or "맞춤 코칭"
+    else:
+        cname = scope.get("course")
+        courses = catalog.get("courses", {})
+        if cname not in courses:
+            raise SystemExit(f"course '{cname}' not in catalog {list(courses)}")
+        lessons = courses[cname]["lessons"]
+        title = courses[cname].get("title", cname)
+
+    items, subtotal = [], 0.0
+    for L in lessons:
+        up = _unit_price(rate, L, mode)
+        amt = up * L["hours"]
+        items.append({"subject": L.get("subject", ""), "title": L.get("title", ""),
+                      "type": L["type"], "hours": L["hours"], "unit_price": up, "amount": amt})
+        subtotal += amt
+
+    students = scope.get("students", 1)
+    apply = scope.get("apply_student_discount", c["student_discount"]["apply_default"])
+    disc = _discount(rate, students, apply)
+    disc_amt = subtotal * disc
+    total = subtotal - disc_amt
+    return {
+        "kind": "coaching", "service": catalog["service"], "label": title,
+        "pricing_mode": mode, "students": students,
+        "discount_rate": disc, "discount_amount": disc_amt,
+        "lessons": items, "subtotal_sum": subtotal, "proposal": int(round(total)),
+        "stub": bool(catalog.get("_stub", False)),
+    }