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  high-risk packaging headache; now superseded.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/USER-GUIDE.md

@@ -103,7 +103,9 @@ The launcher window stays open in the background. Closing it stops the server
 
 - Windows 10/11 (64-bit), macOS 11+, modern Linux (2020+).
 - Modern browser (Chrome, Edge, Firefox, Safari, last 3 years).
-- ~400 MB free disk space (the bundle itself is ~200 MB; the rest is working scratch space for large CSVs).
+- ~500 MB free disk space (the bundle itself is ~300 MB; the rest is working scratch space for large CSVs).
+
+**OCR for scanned PDFs is bundled** — Tesseract 5.5 + the English `eng.traineddata` model ship inside every installer / portable / AppImage. The PDF Extractor's scanned-statement path works out of the box; no separate install required. (Developers running from a `pip install -r requirements.txt` checkout still need system Tesseract on `PATH` — see [DEVELOPER.md §PDF Extractor — bundled Tesseract](DEVELOPER.md#pdf-extractor--bundled-tesseract).)
 
 Full numbered support matrix: [REQUIREMENTS.md](REQUIREMENTS.md).