docs: Add test-first methodology and org-thinking mandates

- Rule 10: Test-first - design tests before coding, run chaos testing
- Rule 11: Org as thinking medium - document investigations in prose
- Rule 12: Engineering decision audit trail - document root cause, tradeoffs

These mandates ensure rigorous verification and capture institutional knowledge.

skills/org-skill-engineering-standards.org

@@ -39,6 +39,27 @@ Source code MUST be strictly free of hardcoded configuration values (e.g., ports
 ** 9. Literate-Only Modification (The Tangle Mandate)
 You are strictly forbidden from modifying generated source code files (e.g., `.lisp`, `.py`, `.el`) directly. All changes MUST be made within the corresponding Literate Org file and then tangled to the source. Direct modification of source code is only permitted with explicit user authorization.
 
+** 10. Test-First Methodology (Design Before Code)
+Before implementing any fix or feature, you MUST:
+1. Design the test/success criteria first - define what "works" means
+2. Run chaos/edge-case testing - try to break the design
+3. Only then implement the solution
+This prevents debugging-by-trial-and-error and ensures rigorous verification.
+
+** 11. Org as Thinking Medium (Investigation in Prose)
+When debugging or analyzing issues:
+1. Document your investigation in the relevant org file BEFORE implementing a fix
+2. Record: root cause hypothesis, evidence found, tradeoffs considered
+3. This makes the reasoning auditable and captures institutional knowledge
+The org file IS the design document - code is just the implementation.
+
+** 12. Engineering Decision Audit Trail
+Every significant fix or architectural decision MUST be documented in the relevant org file with:
+- Root cause analysis
+- Options considered and tradeoffs
+- Why this solution was chosen
+This creates a searchable, literate history of engineering decisions.
+
 * Phase B: Blueprint (PROTOCOL)
 :PROPERTIES:
 :STATUS: SIGNED