docs: define dynamic Living Mission Graph and cross-repo Action DAG

[pcvantol]

Summary

Defines the canonical target for dynamic Mission execution inside one approved Mission and for later cross-repository Action graphs.

• Owner supplies the approved Mission boundary, not an A/B/C script.
• Forge derives Action A, reconciles real EP evidence, replans, and derives B/B2/C as needed until Mission completion is evidence-proven.
• Materialized Actions are immutable; unmaterialized future graph nodes/edges may change from evidence.
• Actions gain a target-repository/write-scope seam and Forge-owned hard depends_on semantics.
• Logical dependency, EP repository/resource exclusion, and EP Agent/provider capacity are explicitly separate.
• Cross-repository artifact evidence can unlock a dependent Action; the EP Agent + Forge Platform installer-role Mission is the reference second canary.
• Updates the canonical Forge roadmap, derived Markdown DAG, and machine-readable DAG with F10 dynamic inner-loop and F11 cross-repository qualification nodes.

Sequencing

The first Forge -> EP -> Forge canary remains serial if necessary but must prove dynamic same-Mission reconcile -> replan -> successor without owner relay. Cross-repository parallel DAG qualification follows it and additionally depends on qualified EP multi-execution/lease/capacity support.

Boundary

This PR changes architecture/roadmap contracts only. It does not touch the concurrent Forge execution-integration implementation PR #46 and does not claim implementation or qualification.