docs(train): setting up and keeping the Loop (ADR 0030, D34)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

docs/adr/0030-halkyon-train.md

@@ -1,6 +1,6 @@
 # ADR 0030: Halkyon Train, what it does and where its data comes from
 
-- **Status:** decided 27–28 Oct 2026, by the developer (D1–D33 below). The shell (D12)
+- **Status:** decided 27–28 Oct 2026, by the developer (D1–D34 below). The shell (D12)
   is built; recording (D13–D28) is built on Android, iOS waiting for a Mac; Health
   Connect (D29) comes next.
 - **Numbering:** 0025 is held by the federation draft (stashed), 0026–0029 by the .NET
@@ -565,6 +565,24 @@ Strava. What was found, 27 Oct:
   band alone, a blank staying blank in Train; a change reaches the band at its next
   connection. The same figures serve calories and heart-rate zones later (D31), on every
   device of the person's. Weight is one current value for now.
+- **D34 Setting up and keeping the Loop** (the developer's; 28 Oct): `profile` one row
+  per person, its fields as D33's (sex female or male, birth date, height in cm, weight
+  in kg, resting and highest heart rate, VO2max, Polar's six training backgrounds, typical
+  day sitting, standing or moving, sleep goal 5 to 11 h), each optional, edited on *Your
+  body* from the account sheet. A *Polar Loop* row there (Android) opens the band's
+  screen; *Set up a Loop* opens a sheet looking for Loops nearby, nearest first; the one
+  chosen is connected through Polar's SDK (Android's pairing dialog may show; nearby
+  devices asked first where not granted), set up with the profile (a short form asks
+  for what is missing, Polar's defaults offered to the band alone), its clock set, and
+  remembered in the person's folder (`loop.json`, not synced: one phone holds it, D3).
+  The band's screen: its name, battery and charging, firmware version, connected or when
+  last seen; *Set up again*; *Let the band go* (a factory reset after asking, the only way
+  to pair it elsewhere). The SDK connects while Train is open and the band in reach, each
+  connection setting its clock and sending what changed in the profile; background
+  syncing is decided with 7b. Firmware moves after 7b, as D10 syncs the band before an
+  update erases it. A Kotlin class of `MainActivity`'s on `app.halkyon.train/loop`, the
+  SDK at 8.3.0 from JitPack (a repository for Polar's package alone, its checksums
+  verified), Polar's notice in the licence list.
 
 ## Consequences