feat(audit): SSDL analysis - effective codepaths + nil-sentinel + organization verdict

- src/code_path_audit_ssdl.py: 9 functions translating per-aggregate findings
  into SSDL primitives (compute_effective_codepaths, count_branches_in_function,
  detect_nil_check_pattern, compute_field_access_efficiency,
  suggest_defusing_technique, render_ssdl_sketch/rollup,
  render_organization_deductions).
- src/code_path_audit.py:render_rollups() now emits ssdl_analysis.md
  + organization_deductions.md alongside the existing 8 rollups.
- src/code_path_audit_render.py:render_full_markdown() adds SSDL sketch
  section per profile (effective codepaths + defusing recommendations).

Real findings (Metadata aggregate):
- 35 consumers, 251 total branches, 1.13e18 effective codepaths
- 6 nil-check functions (candidates for [N] sentinel)
- 130 field-access sites, 0% typed (candidates for immediate-mode cache)
- Verdict: needs restructuring

Audit output grew 2136 -> 2415 lines. All 131 tests pass.
Meta-audit clean (0 violations).

src/code_path_audit_render.py

@@ -10,6 +10,7 @@ from src.code_path_audit import (
  AggregateProfile,
  FunctionRef,
 )
+from src.code_path_audit_ssdl import render_ssdl_sketch
 
 
 def render_full_markdown(profile: AggregateProfile) -> str:
@@ -130,6 +131,9 @@ def render_full_markdown(profile: AggregateProfile) -> str:
    pct = count / len(profile.access_pattern_evidence) * 100
    lines.append(f"- `{pat}`: {count} functions ({pct:.0f}%)")
  lines.append("")
+ # SSDL Sketch (between Access pattern and Frequency)
+ lines.append(render_ssdl_sketch(profile, "src"))
+ lines.append("")
  # Frequency
  lines.append("## Frequency")
  lines.append("")