Time-only universal Helmholtz classification (work package C)

Everything in this subsection is relative to the current coherent presentation ${\mathcal{C}}_{\mathrm{coh}}$ of M.2 ($\dim {\mathcal{C}}_{\mathrm{coh}}=3321$, $\dim {\mathcal{C}}_{\mathrm{reg}}=3150$, K block ${\mathcal{C}}_{\mathrm{K}}=\{N\le 2\}$ of dimension $171$); since Gate S-bv is certified (Theorem thm:wpA-Sbv), no (S-bv) condition remains. Gate V is unchanged: $\eta =\mathrm{diag}(1,-1,-1,-1)$; $\int t_{\mu \nu }{E}^{\mu \nu }=\int {\sum }_{\mu \le \nu }{w}_{\mu \nu }{t}_{\mu \nu }{E}^{\mu \nu }$ with $w=1$ on the diagonal and $w=2$ off it; symmetric lowered $h$; ${\sigma }_{\epsilon }$ and ${\chi }_{\mathrm{I}}$ are fixed under the variation, and their derivatives are retained in every integration by parts. The collapse is the single-switch collapse of Definition def:collapse, $E_C={{\partial }_w}^{\gamma }\bar{a}{|}_{w=y}$ with $a_{\lambda }={\chi }_{\mathrm{I}}{\hat{a}}_{\lambda }$, and there is no second ${\chi }_{\mathrm{I}}$. This subsection supplies the time-only analysis that Proposition prop:fixed-crit (time-only caveat) had left Unresolved.