docs: close BUG-20 (trip IDs renumbered 1..10, sequence clamped)

BUGS.md

@@ -24,24 +24,21 @@ When CLOSED, move the entire entry to Resolved — don't duplicate.
   fills the cards immediately on load (and every 15 s) via REST. Needs in-car
   verification.
 
-### BUG-20 — Server trip IDs inflate far beyond the real trip count
-- **Status**: `OPEN` 2026-08-14
-- **Phase**: 29
-- **Symptom**: the portal shows trip IDs in the tens of thousands (e.g. 25136, 27091) even
-  though there are only ~10 real trips (verified: `COUNT=10`, `MAX(id)=27091`).
-- **Cause**: `trips.id` is `BIGSERIAL`, and `compute_trips_for_device()` upserts every trip on
-  every tracking batch via `INSERT … ON CONFLICT (device_id, start_time) DO UPDATE`. PostgreSQL
-  consumes a sequence value on every INSERT attempt — including the conflict/update path — so
-  the sequence advances by the trip count on every recompute (which runs after every upload
-  batch). Cosmetic only: nothing references `trips.id` as a foreign key (`deleted_trip_markers`
-  keys on `(device_id, start_time)`).
-- **Fix**: clamp the sequence to `MAX(id)` after each recompute in `compute_trips_for_device()`,
-  plus a one-time migration that renumbers existing trips compactly and resets the sequence.
-
 ---
 
 ## Resolved
 
+### BUG-20 — Server trip IDs inflate far beyond the real trip count
+- **Status**: `CLOSED` 2026-08-14
+- **Commit**: `PENDING`
+- **Fix**: `trips.id BIGSERIAL` burned a sequence value on every upsert in
+  `compute_trips_for_device()` (which runs after every upload batch), so IDs climbed far past
+  the real trip count. Now the sequence is clamped to `MAX(id)` after each recompute
+  (`server/modules/db.py`), and a one-time migration (`server/sql/migrate_phase29_trip_ids.sql`)
+  renumbered existing trips compactly and reset the sequence.
+- **Verification**: before — `COUNT=10`, `MAX(id)=27091`; after — `MIN(id)=1`, `MAX(id)=10`,
+  sequence `last_value=10` (next insert gets 11). API container rebuilt and healthy.
+
 ### BUG-18 — Pi needs offline timekeeping (no RTC)
 - **Status**: `CLOSED` 2026-08-14
 - **Commit**: `bf4f3d3`