feat: configurable nutrient dosing schedule with safety guards and Telegram

[m0nk1111]

Summary

Generic hydroponic/aquaponic nutrient dosing schedule function. Configurable for any nutrient brand or feeding chart — not tied to any specific product line.

Features

• 1-8 configurable pumps: Each pump has its own Mycodo output selection, name, and ml/min calibration
• JSON feeding schedule: User provides a JSON object mapping week number to an array of ml/L values per pump. Supports any feeding chart.
• Auto-calculated grow week: From a configurable cycle start date
• Safety features:
  • Flow sensor check with retry/deferral logic (configurable retries and interval)
  • EC pre-check with configurable maximum threshold
  • Per-pump overdose protection with configurable safety factor (default 1.5×)
  • Daily dose tracking prevents double-dosing
• First-week ramp-up: Configurable percentage (default 50%) for gentle start
• Telegram notifications: Optional dose summaries and error alerts
• Custom commands: Dose Now, Show Schedule, Reset First-Week Flag
• Dashboard widget: function_status_always() for persistent display even when deactivated
• InfluxDB logging: Per-pump dose volumes logged for graphing

Schedule Format Example

{
  "1": [2.0, 2.0, 0.0, 2.0, 0.0],
  "2": [2.0, 2.0, 2.0, 2.0, 0.0],
  "3": [2.0, 2.0, 2.0, 2.0, 0.0],
  "4": [2.0, 0.0, 2.0, 2.0, 0.0],
  "5": [2.0, 0.0, 2.0, 2.0, 2.0],
  "6": [0.0, 0.0, 0.0, 2.0, 2.0],
  "7": [0.0, 0.0, 0.0, 0.0, 0.0]
}

Each key is a week number, each value is an array of ml/L/week per pump index (0-based). Week 7 = flush week (all zeros).

Testing

Tested in production on RPi 4B + Mycodo v8.16.2 managing 5 dosing pumps in a hydroponic NFT system running 24/7 for 4+ weeks.

Checklist

• No hardcoded UUIDs or installation-specific values
• No brand-specific references
• All strings in English
• GPL-3.0 license header
• Uses lazy_gettext for translatable labels
• Valid Python syntax
• Follows Mycodo custom function conventions
• Unit tests (to be added before upstream PR)