chore(ocr): polish launch readiness (#409)

Polish the selective OCR runtime documentation, packaging guidance, and cross-language launch smoke coverage.

.github/workflows/ci.yml

@@ -180,18 +180,31 @@ jobs:
           test -n "$ort_path"
           echo "ORT_DYLIB_PATH=$ort_path" >> "$GITHUB_ENV"
 
+      - name: Configure isolated model cache
+        shell: bash
+        run: echo "PDF_INSPECTOR_MODEL_CACHE=$RUNNER_TEMP/pdf-inspector-models" >> "$GITHUB_ENV"
+
       - name: Build OCR CLI
         run: cargo build --features ocr --bin pdf2md
 
       - name: Test PDFium runtime
         run: cargo test --features ocr --test local_render_tests
 
+      - name: Provision OCR model cache
+        shell: bash
+        run: |
+          target/debug/pdf2md \
+            tests/fixtures/scan_with_native_header_text.pdf \
+            --ocr force \
+            --json > /dev/null
+
       - name: Run OCR CLI
         shell: bash
         run: |
           target/debug/pdf2md \
             tests/fixtures/scan_with_native_header_text.pdf \
             --ocr auto \
+            --ocr-offline \
             --json > "$RUNNER_TEMP/ocr-result.json"
 
       - name: Validate OCR JSON contract
@@ -213,6 +226,12 @@ jobs:
           assert "layout_ms" not in result["pages"][0]["timings"]
           PY
 
+      - name: Run OCR launch smoke set
+        shell: bash
+        run: |
+          export PDF_INSPECTOR_OCR_TEST_MODELS="$PDF_INSPECTOR_MODEL_CACHE/pp-ocrv6-small/oar-ocr-v0.7.0"
+          cargo test --features ocr --test ocr_tests -- --nocapture
+
       - name: Build Node binding
         working-directory: napi
         run: |