docs(train): the Loop's own days first (ADR 0030, D32)

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–D31 below). The shell (D12)
+- **Status:** decided 27–28 Oct 2026, by the developer (D1–D32 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
@@ -543,6 +543,19 @@ Strava. What was found, 27 Oct:
   the app opens and comes to the front, and an app turned on brings its earlier
   sessions at once. Not yet tried on a phone.
 
+## The Polar Loop (28 Oct 2026, the developer's)
+
+- **D32 The band's own days first** (recommended, the developer's; over its live heart
+  rate first, and over its setup and sessions alone): 7a setting up and keeping the band
+  (first-time use from Train, its battery, its clock, its firmware as D10 has it); 7b its
+  daily data (steps, active time, calories, 24/7 heart rate, sleep, Nightly Recharge,
+  skin temperature), new synced, sealed models and a first screen of days and nights; 7c
+  its training sessions as workouts; 7d the Loop as live heart rate in a recording
+  without a strap. All-day tracking is what the Loop is for, and its memory must be read
+  regularly or it fills; a strap gives better heart rate in a workout than the wrist.
+  Through Polar's BLE SDK (8.3.0, Polar's permissive licence, its notice kept; from
+  JitPack), which covers the Loop with the Polar 360.
+
 ## Consequences
 
 - Train's sensors are one pattern: open profiles read by the app itself, on the phone;