L21: Quantum-Field Latent Dynamics for JEPA — R3-PARTIAL expansion #697

Lane

L21 expansion of `docs/phd/chapters/21-quantum-field.tex` (R3-PARTIAL per L-PHASE1-R3-PT2 convention, PR #592, lane DELTA).

Refs parent ONE SHOT #265.

Acceptance (R3-PARTIAL contract)

• Edit `docs/phd/chapters/21-quantum-field.tex` in place (no sibling).
• Branch `feat/phd-ch21` from `main`.
• Honest length cap (target 700–1000 lines), R3-PARTIAL marker near top with explicit TODO list.
• ≥1 theorem with full LaTeX proof + `\qedsymbol` + Coq `CorePhi.v` cross-reference (trinity identity `φ²+φ⁻²=3`).
• ≥2 Q1-Q2 citations from existing `docs/phd/bibliography.bib` (Nature/PRL/JMLR/NeurIPS/ICML/ICLR).
• `\section{Falsification Criterion}` block — predictions are CONDITIONAL ("if ablation X is run, threshold Y refutes claim Z"), NOT load-bearing.
• ≥3 atomic commits, each ≤500 lines diff.
• R5-honest: no padding, no Admitted-as-Proven, no fabricated experimental numbers.

Anchor

`phi^2 + phi^-2 = 3` · DOI 10.5281/zenodo.19227877