docs: record observation history decisions

CONTEXT.md

@@ -28,6 +28,10 @@ _Avoid_: Daemon uptime, calibration window
 The single SQLite database at `/var/lib/fenris/observations.db` that persists the observation history, monitoring periods, hour observations, day aggregates, and endurance baseline.
 _Avoid_: Data directory, history.jsonl, the database (generic)
 
+**Pending publication**:
+The condition where valid acquired observations are retained for recovery but their dependent evidence has not yet been published consistently. Those observations are not part of the reader-visible observation history until publication succeeds; readers retain the last consistent evidence with the pending condition made explicit.
+_Avoid_: Successful collection, fresh published evidence
+
 **Store fault**:
 The condition where the observation store is present but cannot be read or trusted — unreadable, corrupt, or written by a newer Fenris — degrading every view that depends on it rather than crashing or guessing.
 _Avoid_: Database error, corruption, broken data
@@ -40,6 +44,18 @@ _Avoid_: Hourly record, hourly.jsonl entry
 One row per UTC day derived from hour observations; the grain at which usage-habit evidence is judged.
 _Avoid_: Daily summary, daily stats
 
+**Local-day evidence**:
+Measured read and write activity attributable to a local calendar day with its recorded timezone and midnight boundaries. Known volumes remain incomplete when gaps or shared local-day evidence prevent an exact total; they are not estimates of the missing activity.
+_Avoid_: Estimated daily total, localised UTC day aggregate
+
+**Shared local-day evidence**:
+Measured read or write volume spanning a local midnight that cannot honestly be allocated to either adjacent day. It is retained once, separately from either day's known volume, rather than prorated or counted in both days.
+_Avoid_: Missing bytes, estimated midnight split
+
+**Activity selection**:
+The read/write measurement, date and point being inspected in live or historical drive activity. Live activity follows the newest point until deliberate inspection pins a point; historical selection survives refresh, while an expired live pin is explained before following resumes.
+_Avoid_: Projection window, current usage habit
+
 **Usage-history window**:
 An exact consecutive span of UTC calendar days ending today, shown from day aggregates; a day without trustworthy evidence remains an explicit gap rather than disappearing or being estimated.
 _Avoid_: Available records, dataset range