Imported Faddeev / Efimov Derivations

These files are preserved derivation notes for the Faddeev/Efimov side of the bridge.

Reading Order

1. 1b-derivation-v2.md - corrected derivation and scalar-split caveat.
2. 1a-derivation-v1.md - earlier derivation note, useful historically.
3. 1c-paper.md - paper-style summary draft.
4. 2-handoff.md and 2b-continue.md - handoff and continuation notes.
5. 3-eigenvalue-flow.md, 3a-math.md, 3b-theorem.md - eigenvalue-flow classification material.

Claim Posture

The theorem/proof language inside this folder is local to the Faddeev/Efimov derivation notes. It does not establish the Spin(2,3) -> Faddeev/Casimir bridge.

Bridge claims are governed by ../casimir-faddeev-conjecture.md and ../proof-obligations.md.