Phases 0-1 + Sprint A: module split, CLI layer, org-refresh fix, hygiene

- LICENSE (MIT) + README truth-pass; docs/cli.md CLI contract
- CLI subcommands (src/cli_cmds/) per "TUI for users, CLI for users+AI"
- Hub/detail refactor: keymap dispatch, modal split, action enum, BgMsg bus
- Fix: org repos were never refreshed (owner==username match); refresh now
  parallel — 49 repos in ~11s, surfaced 70 previously invisible PRs
- Fix: 3 date bugs in detail/git.rs (format-local, Local::now, 1y month math)
- Stash indicator + [m] actions, session persistence, gh CLI token fallback
- Legacy UI modules removed; plan/ docs (roadmap, audit, debate, handoff)

build.rs

@@ -0,0 +1,22 @@
+use std::time::{SystemTime, UNIX_EPOCH};
+
+/// Civil date from days since Unix epoch (Howard Hinnant's algorithm) —
+/// avoids pulling chrono into build-dependencies for one date string.
+fn civil_from_days(z: i64) -> (i64, u32, u32) {
+    let z = z + 719_468;
+    let era = if z >= 0 { z } else { z - 146_096 } / 146_097;
+    let doe = (z - era * 146_097) as u64;
+    let yoe = (doe - doe / 1460 + doe / 36_524 - doe / 146_096) / 365;
+    let y = yoe as i64 + era * 400;
+    let doy = doe - (365 * yoe + yoe / 4 - yoe / 100);
+    let mp = (5 * doy + 2) / 153;
+    let d = (doy - (153 * mp + 2) / 5 + 1) as u32;
+    let m = (if mp < 10 { mp + 3 } else { mp - 9 }) as u32;
+    (if m <= 2 { y + 1 } else { y }, m, d)
+}
+
+fn main() {
+    let secs = SystemTime::now().duration_since(UNIX_EPOCH).map(|d| d.as_secs() as i64).unwrap_or(0);
+    let (y, m, d) = civil_from_days(secs / 86_400);
+    println!("cargo:rustc-env=VULP_BUILD_DATE={y:04}-{m:02}-{d:02}");
+}