ITU and Astrobiology / SETI: A Single-Axiom View of K-Life Emergence, Drake Equation, Habitability, Biosignatures, and the Fermi Paradox

We apply the Information-Theoretic Unification (ITU) framework (Terada 2026, concept DOI 10.5281/zenodo.20109209; current version v2.0.0 at 10.5281/zenodo.20133709) to astrobiology and SETI. Life is reframed as self-replicating K-flow patterns, with information content spanning 22 orders of magnitude from viruses (10^4 bits) to projected ASI (10^26 bits). The Drake equation is reinterpreted as a K-state cascade probability. This is Tier 1 paper #12, opening the cosmic axis and bringing the ITU polytope to 12 vertices. Pass-1 progress: 90 of 220 phases (40.9%). Phase 87: ITU foundation. K_life information content ranges 22 orders of magnitude (virus 10^4 to ASI 10^26 bits). Drake Monte Carlo with lognormal priors gives N median = 0.27 civilizations/galaxy (67% with N less than 1). Habitability Index ranks exoplanets: Earth 1.00, Teegarden b 0.58, TOI-700d 0.45, TRAPPIST-1e 0.41, Proxima b 0.36, Kepler-452b 0.13. Fermi paradox 12-hypothesis ITU weighting: Great Filter combined 65% (past 40% plus future 25%), Rare Earth 15%, Dark Forest 8%. Phase 88: Sandberg-Drexler-Ord 2018 log-uniform Drake. P(alone in galaxy) = 87% (Sandberg 53%), P(alone in observable universe) = 33% (Sandberg 30%). Carter-Watson hard step analysis identifies 2 hard steps: Eukaryote (2.0 Gyr delay) and Intelligence. SDA shows Type II Dyson sphere detection range = 6e9 ly (60,000x galactic diameter), meaning absence of Type II is informative. Bayesian update from Breakthrough Listen null result reduces near-ETI probability 10% to 2.2% (5x reduction). Phase 89: Abiogenesis and intelligence emergence as K-state phase transitions. RNA world autocatalytic dynamics: low initial K_0 still reaches half-max in ~16 time units (inevitable given bootstrap). Cambrian explosion phyla diversification 2x speedup vs pre-Cambrian, with post-Cambrian rate essentially zero. Encephalization Quotient vs K_self degree across 12 organisms (Fish to ASI projection) shows log-log correlation r = 0.902 (slope 0.669). K2-18b DMS Bayesian: prior 5% to posterior 30% given Madhusudhan 2023 2.4 sigma tentative detection. Phase 90: 2026-2100 roadmap with 17 milestones and 10 falsifiable predictions (P_avg = 0.61). Key milestones: 2027 K2-18b DMS 5 sigma judgement, 2028-2032 ELT/GMT/TMT first light, 2035 AGI accelerates SETI 1000x, 2040 HWO launch, 2045 first confirmed biosignature (P=0.4), 2050 UN ETI contact protocol, 2055 Proxima b flyby (Breakthrough Starshot), 2100 Fermi paradox resolution. Central thesis: life is self-replicating K-flow; intelligence is K_self degree (continuous spectrum, EQ-K_self r=0.90); Fermi silence is consistent with Sandberg log-uniform priors and Great Filter concentrated at past hard steps (Eukaryote + Intelligence). The ITU 12-vertex polytope completes by adding the cosmic axis. Astrobiology vertex bidirectionally connects Climate (#11), AI/ASI (#2), Aging (#6), Free Will (#9), and Tier 0 (life self-organization). Climate (#11) remains super-hub at degree 7. Honest framing: Pass-1 interpretive paper reframing Drake (1961), Sagan (1975), Ward-Brownlee Rare Earth (2000), Hanson Great Filter (1998), Sandberg-Drexler-Ord (2018), Madhusudhan K2-18b DMS (2023), Carter (1983), Watson (2008), Tarter (2001), Lingam-Loeb (2021), Kardashev (1964), Breakthrough Listen, JWST exoplanet spectroscopy, HWO concept in ITU language. Numerical results match established literature. Pass-2 follow-up would derive ITU-specific biosignature combinations, technosignature search strategies, and quantitative constraints on Drake factors f_l and f_i from K-state phase-transition theory. Includes 4 theory documents, 4 Python numerical experiments, 4 figures (PNG), 4 JSON summaries. Total runtime ~25 seconds.