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/channel-210-08vt2prib.md

@@ -0,0 +1,101 @@
+# 210-08VT2PRIB BRAND BLEND
+
+- **Vendor:** Bayer
+- **Brand:** Channel
+- **Crop:** Corn
+- **Relative maturity:** 110
+- **Traits:** VT2PRIB (VT Double PRO® RIB Complete® corn blend)
+- **Release year:** 2024
+- **Source:** https://www.cropscience.bayer.us/corn/channel/channel-210-08vt2prib-corn
+- **Rating scale (Bayer):** 1-9 (9 = best)
+
+---
+## Strengths & management
+
+- Broadly adapted 210-08VT2PRIB Brand Blend is a leader in the Channel® brand lineup with top end yield potential and sturdy agronomics
+- Attractive field appearance featuring moderate, consistent ear height and uniform ear size
+- Excellent tolerance to Goss’s wilt plus outstanding greensnap tolerance combine for strong western movement
+- Robust agronomic package showcased by excellent early season growth and solid root and stalk strength
+
+## Maturity
+
+| Characteristic | Value |
+|---|---|
+| GDUS TO BLACK LAYER | 2775 |
+| GDUS TO MID-POLLINATION | 1360 |
+| RELATIVE MATURITY | 110 |
+
+## Agronomic Characteristics
+
+| Characteristic | Value |
+|---|---|
+| DROUGHT TOLERANCE | 3 |
+| DRYDOWN | 2 |
+| EAR FLEX (GRAIN YIELD PER PLANT) | SF |
+| EAR HEIGHT | M |
+| GREENSNAP | 3 |
+| HARVEST APPEARANCE | 3 |
+| PLANT HEIGHT | M |
+| ROOT STRENGTH | 2 |
+| SEEDLING VIGOR | 2 |
+| STALK STRENGTH | 3 |
+| TEST WEIGHT | 4 |
+
+## Disease
+
+| Characteristic | Value |
+|---|---|
+| ANTHRACNOSE STALK ROT | 2 |
+| GOSS'S WILT | 2 |
+| GRAY LEAF SPOT | 4 |
+| NORTHERN CORN LEAF BLIGHT R1 | 5 |
+| SOUTHERN RUST | 6 |
+
+## Adaptation
+
+| Characteristic | Value |
+|---|---|
+| FOCUS AREA | W,C,E |
+
+## Herbicides
+
+| Characteristic | Value |
+|---|---|
+| GROWTH REGULATORS SENSITIVITY | A |
+| PIGMENT INHIBITORS SENSITIVITY | A |
+| SULFONYLUREAS SENSITIVITY | A |
+
+## Other
+
+| Characteristic | Value |
+|---|---|
+| FUSARIUM EAR ROT | Average |
+| KERNEL ROW | 18 |
+| EMERGENCE | 2 |
+| TRAIT | VT2PRIB |
+| VARIETY | 01097250 |
+
+## Regional seed-guide listings
+
+- **2025 Channel Product List NW MO, NE KS, Central MO** — agronomist: Mike Mullins
+- **2025 NE Nebraska** — agronomist: Pat Koenig
+- **2025 Northern Indiana VT2P Product List** — agronomist: Jeff Lakin
+- **2025 Northern Indiana VT2P Product List** — agronomist: Amanda Schwartz
+- **Southwest Iowa** — agronomist: Lance Porter
+- **Northeast MO** — agronomist: Steven Troesser
+- **Channel Products for North Central Iowa** — agronomist: Neal Borgmeyer
+- **2024-2025 East Central NE Corn Grain Product List** — agronomist: Andrew Swanson
+- **Lauren Botine's Product List 2025** — agronomist: Lauren Botine
+- **Eastern VA** — agronomist: Jarette Hurry
+- **SW Ohio Corn, Soybeans, and Silage MY25** — agronomist: Sam Park
+- **2024-2025 South Central NE Corn Grain Product List** — agronomist: Tyler Vreugdenhil
+- **2024/2025 Channel NC Iowa - FSRs Epley and Gehrke** — agronomist: Paul Parcher
+- **2024 SC MN** — agronomist: Tony Weis
+- **2025 West Central Indiana Corn Product List** — agronomist: Blake Russel
+- **South Eastern Indiana Channel Positioning 2025** — agronomist: Cody Hornaday
+- **Ohio Corn, Soybeans, and Silage MY25** — agronomist: Mitchell Greve
+- **2024-2025 South Central NE Corn Silage Product List** — agronomist: Tyler Vreugdenhil
+- **Central & Western VA** — agronomist: Jarette Hurry
+- **2025 Channel Southwest** — agronomist: Mark Bartel
+- **2025 Channel Products for South Dakota** — agronomist: John Goeden
+- **2025 Southwest KS/Southeast CO Corn** — agronomist: Mark Bartel