L02 + L03 + L06: fold in physics-review fixes

Three corrections from the L01-L06 adversarial physics review:

1. CRITICAL: L06 fig_psat_curves H2SO4 latent heat
   720 kJ/kg -> 540 kJ/kg. The lecture's own worked-example table
   in atmospheres_2.md gives L_v/R_v = 6400 K for H2SO4, which
   implies L_v = 540 kJ/kg with R_v = 84.8 J/kg/K. The previous
   720 kJ/kg gave a 33% steeper slope on the H2SO4 psat curve than
   the in-lecture table predicts; students recomputing the curve
   would have got a different answer than the rendered figure.

2. L02 fig_roche_geometry docstring
   Stated 'the crossing defines the fluid Roche limit at 2.17 R_p'
   - actually the curve crossing is the *rigid* Roche limit at
   1.11 R_p (d = R_p (2 rho_p / rho_s)^(1/3)). The fluid Roche
   limit at 2.17 R_p is correctly drawn as a separate dotted
   vertical line. Plot was right; only the docstring was wrong.

3. L03 short_lived_radionuclides.json: 26Al DOI corrected
   The sidecar pointed to 10.1016/0016-7037(94)90419-7 (wrong
   paper); now matches book/references.bib at
   10.1016/S0016-7037(00)00405-X (Lugmair & Galer 2003).

H2SO4 curve regenerated; geomagnetic-polarity AVIF unchanged but
restaged due to seed-deterministic PNG bit-tweak.

Author: timlichtenberg

book/06_atmospheres_2/figures/psat_curves.avif

@@ -6,8 +6,12 @@
     line). Annotates the fluid Roche-limit formula.
 (b) Tidal acceleration across a 200 km icy body and the body's
     surface self-gravity, plotted against orbital distance from
-    Saturn (in units of R_p). The crossing defines the fluid Roche
-    limit at d_R ≈ 2.17 R_p for ρ_s = 1000 kg/m^3.
+    Saturn (in units of R_p). The curve crossing defines the
+    *rigid* Roche limit at d_R ≈ 1.11 R_p for ρ_s = 1000 kg/m^3
+    (i.e. d = R_p (2 ρ_p / ρ_s)^(1/3)). The *fluid* Roche limit at
+    d_R ≈ 2.17 R_p (using the 2.46 prefactor) is drawn as a
+    separate dotted vertical line; tidal stretching of a fluid body
+    becomes catastrophic well before the rigid-body crossover.
 
 Saturn primary used as a concrete example so the figure is consistent
 with the body text. All values derived from public physical

scripts/figures/L02_formation_orbits/fig_roche_geometry.py

@@ -9,7 +9,7 @@
       "value_Myr": 0.717,
       "uncertainty_Myr": 0.024,
       "reference": "Lugmair & Galer (2003)",
-      "doi": "10.1016/0016-7037(94)90419-7"
+      "doi": "10.1016/S0016-7037(00)00405-X"
     },
     "60Fe": {
       "value_Myr": 2.62,

scripts/figures/L03_heat_energy/data/short_lived_radionuclides.json

@@ -16,8 +16,10 @@
 Reference values (literature):
 - H2O: L_vap = 2.50e6 J/kg, T_ref = 373.15 K, P_ref = 101325 Pa
        (boiling point at 1 atm)
-- H2SO4: L_vap = 7.2e5 J/kg, T_ref = 610 K, P_ref = 101325 Pa
-       (boiling point at 1 atm; Pruppacher & Klett 1997)
+- H2SO4: L_vap = 5.40e5 J/kg, T_ref = 610 K, P_ref = 101325 Pa
+       (boiling point at 1 atm; matches the worked-example table in
+       book/06_atmospheres_2/atmospheres_2.md, which gives
+       L_v / R_v = 6400 K for H2SO4)
 - NH3: L_vap = 1.371e6 J/kg, T_ref = 239.7 K, P_ref = 101325 Pa
 - CH4: L_vap = 5.10e5 J/kg, T_ref = 111.7 K, P_ref = 101325 Pa
 - CO2: L_sub = 5.71e5 J/kg, T_ref = 194.7 K, P_ref = 101325 Pa
@@ -41,7 +43,7 @@
 # (label, M [kg/mol], L [J/kg], T_ref [K], P_ref [Pa], color, condensation_T_band [K, K])
 SPECIES = [
     (r"H$_2$O",   18.015e-3, 2.50e6, 373.15, 101325.0, "#1f77b4", (250, 320)),
-    (r"H$_2$SO$_4$", 98.08e-3, 7.2e5, 610.0,  101325.0, "#d62728", (300, 420)),
+    (r"H$_2$SO$_4$", 98.08e-3, 5.40e5, 610.0, 101325.0, "#d62728", (300, 420)),
     (r"NH$_3$",   17.031e-3, 1.371e6, 239.7,  101325.0, "#2ca02c", (130, 180)),
     (r"CH$_4$",   16.043e-3, 5.10e5, 111.7,  101325.0, "#ff7f0e", (90, 150)),
     (r"CO$_2$ (subl.)", 44.01e-3, 5.71e5, 194.7, 101325.0, "#9467bd", (110, 180)),