DIRECT PRODUCT KEYWORD SYSTEM - V7

Customer can type a product/service name directly instead of opening Menu.

Examples:
- PRIME VIDEO -> bot finds all active Prime Video matches from live products table.
  If there are multiple matches, bot replies "Select your Product" with numbered options.
- PRIME VIDEO 1 MONTH -> exact active product name wins and starts that product directly.
- NETFLIX -> only Netflix matching products are shown.
- QUILLBOT -> if only one matching product exists, bot starts that product purchase flow directly.

Live checks:
- Direct/OTP products: product_stock must contain available stock.
- Manual delivery: treated as On Demand.
- IPTV/Opplex: treated as generated/available, same as existing bot behavior.
- If all matches are unavailable: immediate NOT IN STOCK reply.
- Wallet customers: if they cannot afford even the cheapest available match, immediate INSUFFICIENT FUNDS reply.
- On multi-product lists, each unavailable/unaffordable option is labelled. Selecting one re-checks stock and wallet balance live.

No hard-coded Prime Video / Netflix / Quillbot products were added. Matching uses whatever active products/categories already exist in Admin.
