feat(routes): add per-route max_path_length cap

[jinglemansweep]

Summary

Adds a new nullable per-route knob max_path_length that caps the total number of hops in a candidate packet's path. Packets whose path exceeds the cap are dropped from matching consideration entirely (before the subsequence matcher runs), so over-long paths never count toward packet_count_threshold.

Complements the existing max_hop_span, which only constrains the gap between the first and last matched configured node. The new knob constrains the total packet path size and drops over-long packets up front.

Semantics

• Field name: max_path_length
• Type: Optional[int] (null = unlimited)
• Default: null (backwards-compatible — existing routes unchanged)
• Check: len(hops) > max_path_length → reject, before running the subsequence match

Changes

Data layer

• Route model: new max_path_length column (nullable Integer, default null)
• Migration d307ee761a34 (additive, no backfill, zero-downtime)

Matcher (collector/routes.py)

• Early-return check added to _subsequence_indices; threaded through is_subsequence, _matched_subpath, _matched_subpath_with_indices, _match_hops
• All 5 call sites updated: evaluate_route, evaluate_route_day, evaluate_route_history, recent_matches, preview_route

API + CLI

• Schemas: RouteCreate, RouteUpdate, RouteRead, RouteDetail, RoutePreviewRequest
• API serializer / create / update / preview passthrough
• CLI seed YAML import (update + create paths)

Frontend

• Two new dedicated icons: iconHopSpan (<-o->) for max_hop_span, iconPathLength (|⟷|) for max_path_length — distinct from each other and from the generic iconPath
• Both badges now always render with ∞ fallback when null (mirrors observer-count pattern)
• Hover tooltips added to every stats row item with i18n labels (en + nl)

Tests

• Matcher unit tests: test_path_length_cap_within, test_path_length_cap_exceeds, test_path_length_cap_zero_ignored
• API round-trip: test_update_all_scalar_fields extended to PUT max_path_length: 6 and assert round-trip
• CLI seed import test extended with max_path_length: 12

Verification

pytest --no-cov tests/test_collector/test_routes.py tests/test_api/test_routes.py tests/test_collector/test_cli.py
# 163 passed
pre-commit run --all-files  # all green

Out of scope

• No cache invalidation changes (invalidate_routes already covers all route mutations)
• No configuration.md change (per-route DB field, not env var)
• No data backfill (column is nullable, defaults null = unlimited)
• Migration is additive and backwards-compatible with running collectors

[codecov]

Codecov Report

❌ Patch coverage is 85.00000% with 3 lines in your changes missing coverage. Please review.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/meshcore_hub/collector/routes.py	72.72%	0 Missing and 3 partials ⚠️

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