refactor(B05,B06): B05_wf2_Route -> B05_Profile, B06_wf3_ProfileCross -> B06_Section 동시 개명

- 한몸으로 동작하는 두 페이지라 한 커밋으로 처리 (상호 참조 다수)
- B05 37파일 + B06 20파일 접두사 개명 (git mv, 이력 보존)
- 참조 치환 91파일: import 경로, 라우트 슬러그(b05-profile/b06-section),
  라우트 키(B05_PROFILE/B06_SECTION), B03 자동 체인, storage 상수, pyproject 제외 경로
- 로직 변경 없음. typecheck·백엔드 import 검증 통과

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

db_management/001_create_schema.sql

@@ -292,7 +292,7 @@ CREATE TABLE IF NOT EXISTS routes (
   grade_percent JSON,                       -- [2.5, 1.8, 3.2, ...] 각 구간 경사도
   constraints JSON,                         -- max_grade, min_radius, avoidance_zones
   algorithm_params JSON,                    -- cost_weights, ...
-  route_data_path VARCHAR(500),             -- storage/.../B05_wf2_Route/route/...
+  route_data_path VARCHAR(500),             -- storage/.../B05_Profile/route/...
   computed_at TIMESTAMP NULL DEFAULT NULL,
   created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
@@ -333,7 +333,7 @@ CREATE TABLE IF NOT EXISTS longitudinal_sections (
   route_id INT NOT NULL,                    -- FK는 later
   computed_at TIMESTAMP NULL DEFAULT NULL,
   data JSON,                                -- chainages, elevations, grades, design_elevations
-  longitudinal_file_path VARCHAR(500),      -- storage/.../B06_wf3_ProfileCross/longitudinal/...
+  longitudinal_file_path VARCHAR(500),      -- storage/.../B06_Section/longitudinal/...
   status VARCHAR(50) DEFAULT 'DRAFT'        -- DRAFT, CONFIRMED
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
 
@@ -345,7 +345,7 @@ CREATE TABLE IF NOT EXISTS cross_sections (
   chainage_m FLOAT,
   sequence_num INT,
   data JSON,                                -- left_slope, right_slope, width_m, cut_volume_m3, fill_volume_m3, structures, notes
-  cross_section_file_path VARCHAR(500),     -- storage/.../B06_wf3_ProfileCross/cross_sections/...
+  cross_section_file_path VARCHAR(500),     -- storage/.../B06_Section/cross_sections/...
   status VARCHAR(50) DEFAULT 'DRAFT'        -- DRAFT, CONFIRMED
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;