feat(analysis): add in-process ocrs OCR backend

Add a CPU-only, English-first OCR engine (the `ocrs` crate on the `rten`
runtime) as an alternative to the local-LLM "vision" backend, which ran
too slowly on the target Raspberry Pi 5.

- `ANALYSIS_BACKEND` (default `ocr`) selects the engine; `vision` keeps the
  existing LLM path. Deploy-time, env-only — not admin-tunable.
- `analysis::ocr` adds an `OcrEngine` trait (testable seam), the `OcrsEngine`
  impl (models loaded once, inference on the blocking pool), and an
  `OcrAnalyzeDispatcher` that plugs into the existing `AnalyzeDispatcher`
  seam and reuses `persist_analysis`, so OCR text lands in `page_ocr_text`
  and the `search_doc` tsvector exactly as the vision path produces them.
- The backend image bakes the two `.rten` models into /models, where
  `OCRS_DETECTION_MODEL` / `OCRS_RECOGNITION_MODEL` default.

Because `/v1/me/page-search` ranks on `search_doc`, OCR text search works
the moment pages are processed. Auto-tagging, scene description and NSFW
flags remain the vision backend's job (deferred).

Bumps to 0.90.0 (minor) in both manifests.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docker-compose.yml

@@ -143,8 +143,13 @@ services:
       # when both are present. Leave unset for the bundled
       # HashedControlPassword path above.
       CRAWLER_TOR_CONTROL_COOKIE_PATH: ${CRAWLER_TOR_CONTROL_COOKIE_PATH:-}
-      # Analysis worker (vision) — boot seeds + env-only API key.
+      # Analysis worker — boot seeds + env-only API key.
       ANALYSIS_ENABLED: ${ANALYSIS_ENABLED:-false}
+      # Engine selection (deploy-time): `ocr` (in-process ocrs, default) or
+      # `vision` (local LLM). Model paths default to the image-baked /models.
+      ANALYSIS_BACKEND: ${ANALYSIS_BACKEND:-ocr}
+      OCRS_DETECTION_MODEL: ${OCRS_DETECTION_MODEL:-/models/text-detection.rten}
+      OCRS_RECOGNITION_MODEL: ${OCRS_RECOGNITION_MODEL:-/models/text-recognition.rten}
       ANALYSIS_VISION_URL: ${ANALYSIS_VISION_URL:-}
       ANALYSIS_VISION_MODEL: ${ANALYSIS_VISION_MODEL:-}
       ANALYSIS_WORKERS: ${ANALYSIS_WORKERS:-1}