first implementation - image/drawing integration

backend/src/main/resources/application.yaml

@@ -47,6 +47,16 @@ spring:
         max-size: 8
         queue-capacity: 50
 
+logging:
+  level:
+    "[org.apache.pdfbox]": ERROR
+
 app:
   auth:
     password: ${APP_PASSWORD:changeme}
+  figure-storage:
+    base-path: ${FIGURE_STORAGE_PATH:./uploads}
+    min-image-size-px: 100
+  embedding:
+    batch-size: 20
+    batch-delay-ms: 2000

backend/src/main/resources/db/migration/V4__document_hierarchy.sql

@@ -0,0 +1,28 @@
+-- ============================================================
+-- V4: Document hierarchy — chapter and section tables
+-- Supports parent-child retrieval pattern for RAG precision.
+-- ============================================================
+
+CREATE TABLE IF NOT EXISTS chapter (
+    id           VARCHAR(200) PRIMARY KEY,
+    book_id      UUID NOT NULL REFERENCES book(id) ON DELETE CASCADE,
+    number       INT NOT NULL DEFAULT 1,
+    title        VARCHAR(500),
+    page_start   INT,
+    created_at   TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+CREATE TABLE IF NOT EXISTS section (
+    id           VARCHAR(200) PRIMARY KEY,
+    chapter_id   VARCHAR(200) NOT NULL REFERENCES chapter(id) ON DELETE CASCADE,
+    book_id      UUID NOT NULL REFERENCES book(id) ON DELETE CASCADE,
+    number       VARCHAR(50),
+    title        VARCHAR(500),
+    page_start   INT NOT NULL,
+    page_end     INT NOT NULL,
+    full_text    TEXT NOT NULL,
+    created_at   TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+CREATE INDEX IF NOT EXISTS idx_section_book    ON section(book_id);
+CREATE INDEX IF NOT EXISTS idx_section_chapter ON section(chapter_id);

backend/src/main/resources/db/migration/V5__figures_and_refs.sql

@@ -0,0 +1,29 @@
+-- ============================================================
+-- V5: Figures and chunk-to-figure reference table
+-- figure: metadata + file path for each extracted image
+-- chunk_figure_ref: links vector-store chunks to figures
+-- ============================================================
+
+CREATE TABLE IF NOT EXISTS figure (
+    id                    VARCHAR(200) PRIMARY KEY,
+    book_id               UUID NOT NULL REFERENCES book(id) ON DELETE CASCADE,
+    section_id            VARCHAR(200) REFERENCES section(id) ON DELETE SET NULL,
+    chapter_id            VARCHAR(200) REFERENCES chapter(id) ON DELETE SET NULL,
+    label                 VARCHAR(100),
+    caption               TEXT,
+    figure_type           VARCHAR(50) NOT NULL,
+    page                  INT NOT NULL,
+    image_path            VARCHAR(1000) NOT NULL,
+    caption_embedding_id  UUID,
+    created_at            TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+CREATE TABLE IF NOT EXISTS chunk_figure_ref (
+    chunk_id      UUID NOT NULL,
+    figure_id     VARCHAR(200) NOT NULL REFERENCES figure(id) ON DELETE CASCADE,
+    mention_page  INT,
+    PRIMARY KEY (chunk_id, figure_id)
+);
+
+CREATE INDEX IF NOT EXISTS idx_figure_book  ON figure(book_id);
+CREATE INDEX IF NOT EXISTS idx_cfr_chunk    ON chunk_figure_ref(chunk_id);