docs: reflect bundled Tesseract on every install surface

- NEW LICENSE_TESSERACT.txt at the repo root: header noting it covers
  the bundled Tesseract OCR binary (Apache 2.0, upstream
  tesseract-ocr/tesseract, copyright Google + contributors) and the
  eng.traineddata from tessdata_best (also Apache 2.0). Clarifies
  DataTools itself remains proprietary. Full canonical Apache 2.0
  license text included.
- README.md + README.es.md (Download section): bumped size estimate
  ~200 MB → ~300 MB, added a short paragraph stating Tesseract OCR
  is bundled (no separate install required), with a link to the new
  license file.
- docs/USER-GUIDE.md + docs/USER-GUIDE.es.md (§1.6 System
  requirements): bumped disk estimate, added a paragraph stating
  Tesseract 5.5 + eng.traineddata ship inside every installer /
  portable / AppImage, with a source-install fallback hint pointing
  developers to DEVELOPER.md.
- docs/DEVELOPER.md: new "PDF Extractor — bundled Tesseract" section
  documenting the runtime layout (sys._MEIPASS / tesseract / …),
  discovery order, source of bytes (build/vendor/tessdata + per-
  platform fetch in make_release.py), version pin, update recipe.
- docs/TECHNICAL.md: new §3.10 "Bundled Tesseract (PDF Extractor
  OCR)" — short version of the discovery order for the build
  pipeline section.
- build/README.md: distribution-outputs paragraph now lists
  Tesseract among bundled deps with the ~250-300 MB estimate; new
  "Tesseract bundling" section: layout diagram, resolver order,
  source of bytes + 5.5.0 pin, update steps, license-file ref.

Out-of-scope gaps noted by the docs sweep:
- docs/FUTURE-TOOLS.md §D still describes Tesseract bundling as a
  high-risk packaging headache; now superseded. Worth a one-line
  "(resolved — bundled as of v1.x)" callout in a future pass.
- USER-GUIDE §2 "What's included" table doesn't list PDF Extractor
  at all (it shipped in b8aff86…967d3f6). Separate gap to close.

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

docs/TECHNICAL.md

@@ -122,6 +122,17 @@ Tag a release → 3 platform artifacts upload to GitHub Releases. Manual: copy t
 
 `demo/streamlit_app.py` → Streamlit Community Cloud. Configure deployment in Streamlit UI. Custom domain via CNAME (verify policy at deploy time). Fall back to $5/mo VPS if rate limits / branding constraints hit.
 
+### 3.10 Bundled Tesseract (PDF Extractor OCR)
+
+Frozen builds ship Tesseract 5.5 + `eng.traineddata` inside the PyInstaller bundle so scanned PDFs work without a separate install. Per-platform binary URLs pinned in `build/make_release.py`; tessdata vendored at `build/vendor/tessdata/eng.traineddata`. License attribution in `LICENSE_TESSERACT.txt` at the repo root.
+
+**Discovery order at runtime** (see `docs/DEVELOPER.md` for the full Path layout):
+
+1. `DATATOOLS_TESSERACT_BIN` env var override.
+2. Bundled path under `sys._MEIPASS / "tesseract" /` (frozen bundles only).
+3. `tesseract` on `PATH` (source / pip developer environments).
+4. Windows well-known locations.
+
 ## 4. Libraries
 
 | Purpose | Library |