v0.4.5 — structural_violation smell, two-tier complexity, structural integrity docs

Structural integrity

New: structural_violation smell

borescope smells now reports structural_violation when a function exceeds hard structural limits — regardless of hotspot score or fanin count:

• complexity > 22 (cyclomatic complexity absolute limit)
• loc > 200 (per-function LOC absolute limit)

This is distinct from high_complexity_bottleneck which requires complexity + fanin + hotspot to all exceed thresholds simultaneously. A cold function with complexity 32 won't trigger the bottleneck smell but will trigger structural_violation.

Two-tier threshold design

# .borescope/thresholds.toml
[default]
# Hard structural limits — structural_violation fires regardless of hotspot/fanin
complexity_absolute = 22
loc_high            = 200

# Compound bottleneck — needs ALL THREE conditions
complexity_high = 10
fanin_high      = 8
hotspot_medium  = 0.5

Docs: structural integrity section in patterns.md

Every heuristic now has:

• What it measures (with Wikipedia/research reference)
• The absolute target value
• The borescope command that surfaces it
• Clear separation of what borescope covers vs. external tools (tarpaulin, cargo-mutants)

'Quality heuristics' renamed to 'Structural integrity' throughout — these are objective structural properties, not style preferences.