docs: Update alarm and office READMEs with design decisions

[jarvis-tsang]

This PR updates documentation for:

• Alarm package — Auto-generated README with human-friendly automation descriptions
• Office package — Added Design Decisions and Dependencies sections to existing rich README

Changes

• Design Decisions section capturing architectural rationale (temperature thresholds, time delays, etc.)
• Dependencies section linking related packages (Front Garden, Living Room, Porch)
• Enhanced mermaid diagrams showing data flow
• Updated 'Last updated' dates

Design Decisions Captured

• Temperature thresholds based on summer room temperatures
• Time delays account for temporary disconnections
• Sun position tracking for daylight-aware behavior
• Enable switches for easy automation disabling
• Edge detection vs continuous state triggers

Dependencies Documented

• EcoFlow integration for energy optimization
• Cross-package dependencies (Front Garden brightness sensor, Living Room presence groups, Porch notifications)