feat: Add housekeeping stream and greenfield capability as Rules 4 and 5

move-fast-and-fix-things.md: Three Rules -> Five Rules.
Rule 4: Housekeeping as a permanent stream (named owner, cadence, queue).
Rule 5: Greenfield capability as standard operational activity every 5 years.
Updated pillar mapping table.

antifragile-manifest.md: Pillar 1 Antifragile Moves: greenfield capability
as the ultimate expression of structural decoupling. Controlled burn framing.

Co-Authored-By: Tom Kracmar <tom+claude@cat6.cz>

antifragile-consulting/core/antifragile-manifest.md

@@ -47,6 +47,7 @@ Cloud architectures have created an illusion of resilience through scale. In rea
 - **Design graceful degradation**: Every critical function must have a fallback mode that operates at reduced capacity without the external dependency.
 - **Practice controlled failure**: Introduce chaos into non-production environments. If a system cannot survive the simulated failure of a dependency, it will not survive the real one.
 - **Establish exit architectures**: For every major platform dependency, maintain a technical and procedural path to migration that can be executed within 90 days.
+- **Build greenfield capability**: The ultimate expression of structural decoupling is the ability to rebuild the entire environment from scratch — cleanly, from documentation and version-controlled configuration, without inheriting the compromised state. An organisation that can execute a planned greenfield deployment every five years or so is in a structurally different risk position than one for which greenfield is a nightmare scenario. This is the controlled burn: organisations that never rebuild accumulate the technical debt and undocumented dependencies that make eventual failure catastrophic. See [Move Fast and Fix Things — Rule 5](move-fast-and-fix-things.md#rule-5-build-toward-greenfield-capability).
 
 ### Executive Framing