bayer_seeds: add Channel + DEKALB silage/sorghum/canola + Deltapine cotton

User flagged that Channel is expanding into their area — re-walked
the cropscience.bayer.us sitemap and found 8 additional brand×crop
paths beyond the original DEKALB/Asgrow/WestBred triple. Patches
the scraper to walk all of them; total Bayer varieties roughly
doubles from 475 to 931 and the corpus picks up first-ever
coverage in sorghum (36), cotton (30), canola (6), and silage as a
distinct crop (was conflated with corn before).

Net new varieties: 456
  Channel    corn=181  soy=67   silage=54  sorghum=18    (320)
  DEKALB     silage=82 sorghum=18  canola=6              (106)
  Deltapine  cotton=30                                    (30)

scrape/sources/bayer_seeds.py
- Replace `BRANDS` (brand → 1 path) and `CROP_SUFFIX` (brand → 1
  suffix) with a flatter `BRAND_PATHS` list of (brand, url_path,
  crop, is_primary_for_brand) entries. Channel and DEKALB are now
  multi-crop brands; the same scraper walks every brand×crop pair.
- source_key derivation: for a brand's PRIMARY crop, strip the
  trailing `-<crop>` suffix (matches the existing deployed source
  keys for DEKALB corn / Asgrow soy / WestBred wheat). For
  SECONDARY crops, KEEP the suffix so DEKALB-the-same-SKU sold as
  both grain corn and silage gets two distinct source_keys
  (collision-safe and unambiguous for `lookup_variety`).
- New `--crop` CLI filter for incremental backfills.
- Log line shows brand + crop alongside source_key for visibility.

rag/chunk.py
- Channel + Deltapine pages use slightly different characteristics
  group labels (DISEASE not DISEASE RATINGS, AGRONOMIC
  CHARACTERISTICS not GROWTH/HARVEST, plus MATURITY / ADAPTATION /
  HERBICIDES / OTHER). Fold them into the DISEASE / AGRONOMIC /
  MANAGEMENT label sets so the chunker buckets them correctly
  into the standard sections.

Smoke-tested cross-brand × cross-crop queries against the rebuilt
index (5,529 chunks total) — all 6 sample queries surface the
right brand+crop at top-3:
  Channel corn 110 RM       → 210-25TRE BRAND
  Channel soy 2.5 MG IA     → 2622RXF BRAND
  Deltapine cotton XF       → DP 1820 B3XF BRAND
  Sorghum dryland Kansas    → 6B95 BRAND (Channel)
  Silage corn WI dairy      → DKC64-44RIB BRAND BLEND (silage variant)
  Canola Northern Plains    → DK401TL BRAND

Watchtower will pull the new image on the next push; deploy is
unchanged otherwise.

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

corpus/bayer_seeds/dekalb-dkc56-65rib-silage.md

@@ -0,0 +1,103 @@
+# DKC56-65RIB BRAND BLEND
+
+- **Vendor:** Bayer
+- **Brand:** Dekalb
+- **Crop:** Silage
+- **Traits:** SSRIB (SmartStax® RIB Complete® corn blend)
+- **Release year:** 2021
+- **Source:** https://www.cropscience.bayer.us/silage/dekalb/dekalb-dkc56-65rib-silage
+- **Rating scale (Bayer):** 1-9 (9 = best)
+
+---
+## Positioning
+
+DKC56-65RIB Brand Blend is a 106 RM hybrid that can offer a grower standout yield potential balanced with solid agronomics.  It has shown a very good foliar disease package as well as harvest appearance.
+
+## Strengths & management
+
+- Product can provide very good emergence and seedling vigor for early planting
+- Can provide utilization in field with known physoderma history
+- Hybrid has shown food grade potential
+- Has shown an attractive shorter plant profile with excellent root and stalk strength
+- Has show good utilization in corn following corn rotations
+- May benefit from a fungicide in heavy Gray Leaf Spot fields
+- Position on medium to higher productivity soils for best performance
+
+## Management
+
+| Characteristic | Value |
+|---|---|
+| VALUE ADDED TRAIT | SSRIB |
+| RELATIVE MATURITY | 106 |
+| GDUS TO MID-POLLINATION | 1325 |
+| GDUS TO BLACK LAYER | 2650 |
+| PLANTING RATE | Med High |
+| SILAGE PROVEN | No |
+| NEW PRODUCT | NO |
+| VARIETY | 01080705 |
+
+## Plant Description
+
+| Characteristic | Value |
+|---|---|
+| COB COLOR | Red |
+| KERNEL CAP COLOR | Yellow |
+| KERNEL ROW | 18 |
+
+## Growth
+
+| Characteristic | Value |
+|---|---|
+| EMERGENCE | 2 |
+| SEEDLING GROWTH | 2 |
+| ROOT STRENGTH | 2 |
+| STALK STRENGTH | 2 |
+| DROUGHT TOLERANCE | 3 |
+| GREENSNAP | 3 |
+| PLANT HEIGHT | Med Short |
+| EAR PLACEMENT | Med Low |
+
+## Harvest
+
+| Characteristic | Value |
+|---|---|
+| STAYGREEN | 2 |
+| HARVEST APPEARANCE | 2 |
+| DRYDOWN | 3 |
+| TEST WEIGHT | 3 |
+
+## Diseases
+
+| Characteristic | Value |
+|---|---|
+| NORTHERN CORN LEAF BLIGHT | 3 |
+| GRAY LEAF SPOT | 5 |
+| SOUTHERN RUST | 6 |
+| ANTHRACNOSE STALK ROT | 3 |
+| GOSS'S WILT | 4 |
+
+## Herbicide
+
+| Characteristic | Value |
+|---|---|
+| GROWTH REGULATORS SENSITIVITY | A |
+| SULFONYLUREAS SENSITIVITY | A |
+| ISOXAZOLES SENSITIVITY - PRE-EMERGENCE | A |
+
+## Silage Characteristics
+
+| Characteristic | Value |
+|---|---|
+| NDFD 24 HR | 3 |
+| NDFD 30 HR | 2 |
+| % OF STARCH | 4 |
+| IVSD7HR | 2 |
+| SILAGE YIELD | 3 |
+| MILK PER TON | 3 |
+| MILK PER ACRE | 3 |
+
+## Regional seed-guide listings
+
+- **2024 South Dakota Product Guide** — agronomist: Gary Hegg
+- **2024 South Dakota Product Guide** — agronomist: Jeff Spieler
+- **2024 Northern IL Local Recommendations** — agronomist: Jim Donnelly