feat: Smart Capture configurable trigger sub-settings and Connection Monitor integration

[itsDNNS]

Summary

Adds per-trigger sub-settings for fine-grained control over when Smart Capture fires, and wires Connection Monitor packet loss events into the engine as a 5th trigger source.

Shared DOCSIS Utility

• Extracted QAM_ORDER + qam_rank() from event_detector.py to app/docsis_utils.py
• EventDetector now materializes prev_rank/current_rank in modulation change event details

Sub-Filter Architecture

• Trigger dataclass extended with sub_filter: Callable field
• 5 filter functions in app/smart_capture/sub_filters.py using qualifying-subset logic (any matching change triggers)
• Engine applies sub-filter after config_key toggle check, before guardrails

Per-Trigger Sub-Settings

• Modulation: Direction (DS/US/Both) + Min QAM level dropdown (Any/Below 256QAM/64QAM/16QAM)
• SNR: No sub-settings in v1 (DS-only detection)
• Error spike: Min error delta (0 = any spike)
• Health: Level filter (Any degradation / Critical only)
• Packet loss (new): Toggle + Min % threshold with coupling hint

Connection Monitor Wiring

• set_smart_capture() method on CM Collector for post-construction injection
• CM uses save_events_with_ids() for event ID annotation
• Evaluates events through Smart Capture engine after save

Settings UI

• Trigger cards with expandable sub-settings (show/hide on toggle)
• Packet loss card with Connection Monitor coupling hint
• CSS transitions for sub-settings visibility

i18n

• 19 new keys across EN/DE/FR/ES with proper German umlauts

Closes #245

Test plan

• 18 sub-filter unit tests (direction, QAM threshold, qualifying-subset, error delta, health level, packet loss)
• 116 Smart Capture tests pass
• 1701 total tests pass (0 failures)
• i18n validation passes (39 language files in sync)