feat: surface LN1/LN2 (L1/L10) percentiles through SLMM

Completes the SLMM side of the L1/L10 live-display contract. The NL-43's
DOD response carries percentile slots LN1-LN5 (channel 1, parts[5]/[6]);
parse the first two and expose them as ln1/ln2 end to end:

- NL43Snapshot dataclass: ln1/ln2 fields
- NL43Status model: ln1/ln2 columns (+ migrate_add_ln_percentiles.py)
- DOD parser: snap.ln1=parts[5], snap.ln2=parts[6]
- persist_snapshot writes them
- all /status data dicts, StatusPayload, and the DRD stream payload emit
  ln1/ln2 (null on the DRD stream itself, which doesn't carry percentiles)

Labels: device LN1 defaults to L5, not L1 — Terra-View defaults the label
to L1/L10, so the device's Ln1/Ln2 slots must be set to 1%/10% for the
labels to be accurate (dynamic label emission is a follow-up).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/models.py

@@ -41,6 +41,8 @@ class NL43Status(Base):
     lmax = Column(String, nullable=True)  # Maximum level
     lmin = Column(String, nullable=True)  # Minimum level
     lpeak = Column(String, nullable=True)  # Peak level
+    ln1 = Column(String, nullable=True)  # Percentile slot LN1 (configurable; device default L5, contract L1)
+    ln2 = Column(String, nullable=True)  # Percentile slot LN2 (configurable; device default L10)
     battery_level = Column(String, nullable=True)
     power_source = Column(String, nullable=True)
     sd_remaining_mb = Column(String, nullable=True)

app/routers.py

@@ -450,6 +450,8 @@ def get_status(unit_id: str, db: Session = Depends(get_db)):
             "lmax": status.lmax,
             "lmin": status.lmin,
             "lpeak": status.lpeak,
+            "ln1": status.ln1,
+            "ln2": status.ln2,
             "battery_level": status.battery_level,
             "power_source": status.power_source,
             "sd_remaining_mb": status.sd_remaining_mb,
@@ -472,6 +474,8 @@ class StatusPayload(BaseModel):
     lmax: str | None = None
     lmin: str | None = None
     lpeak: str | None = None
+    ln1: str | None = None
+    ln2: str | None = None
     battery_level: str | None = None
     power_source: str | None = None
     sd_remaining_mb: str | None = None
@@ -504,6 +508,8 @@ def upsert_status(unit_id: str, payload: StatusPayload, db: Session = Depends(ge
             "lmax": status.lmax,
             "lmin": status.lmin,
             "lpeak": status.lpeak,
+            "ln1": status.ln1,
+            "ln2": status.ln2,
             "battery_level": status.battery_level,
             "power_source": status.power_source,
             "sd_remaining_mb": status.sd_remaining_mb,
@@ -1205,6 +1211,8 @@ async def stream_live(websocket: WebSocket, unit_id: str):
                     "lmax": snap.lmax,  # Maximum level
                     "lmin": snap.lmin,  # Minimum level
                     "lpeak": snap.lpeak,  # Peak level
+                    "ln1": snap.ln1,    # LN1 percentile (L1/L10 contract); null on DRD stream
+                    "ln2": snap.ln2,    # LN2 percentile; null on DRD stream
                     "raw_payload": snap.raw_payload,
                 })
             except Exception as e:
@@ -1876,6 +1884,8 @@ async def run_diagnostics(unit_id: str, db: Session = Depends(get_db)):
             "lmax": status.lmax,
             "lmin": status.lmin,
             "lpeak": status.lpeak,
+            "ln1": status.ln1,
+            "ln2": status.ln2,
             "battery_level": status.battery_level,
             "power_source": status.power_source,
             "sd_remaining_mb": status.sd_remaining_mb,

app/services.py

@@ -46,6 +46,8 @@ class NL43Snapshot:
     lmax: Optional[str] = None  # Maximum level
     lmin: Optional[str] = None  # Minimum level
     lpeak: Optional[str] = None  # Peak level
+    ln1: Optional[str] = None  # Percentile slot LN1 (configurable; device default L5, contract L1)
+    ln2: Optional[str] = None  # Percentile slot LN2 (configurable; device default L10)
     battery_level: Optional[str] = None
     power_source: Optional[str] = None
     sd_remaining_mb: Optional[str] = None
@@ -108,6 +110,8 @@ def persist_snapshot(s: NL43Snapshot, db: Session):
         row.lmax = s.lmax
         row.lmin = s.lmin
         row.lpeak = s.lpeak
+        row.ln1 = s.ln1
+        row.ln2 = s.ln2
         row.battery_level = s.battery_level
         row.power_source = s.power_source
         row.sd_remaining_mb = s.sd_remaining_mb
@@ -716,9 +720,10 @@ class NL43Client:
                 snap.lmin = parts[4]    # Lmin
             if len(parts) >= 11:
                 snap.lpeak = parts[10]  # Lpeak  (parts[5] is LN1, NOT Lpeak)
-            # LN1/LN2 percentiles live at parts[5]/parts[6] (the L1/L10 display contract).
-            # Surfaced as snap.ln1/snap.ln2 once those fields are added to the snapshot
-            # dataclass + NL43Status model — next step on this branch.
+            if len(parts) >= 6:
+                snap.ln1 = parts[5]     # LN1 percentile slot (device default L5; contract L1)
+            if len(parts) >= 7:
+                snap.ln2 = parts[6]     # LN2 percentile slot (device default L10)
         except (IndexError, ValueError) as e:
             logger.warning(f"Error parsing DOD data points: {e}")
 

migrate_add_ln_percentiles.py

@@ -0,0 +1,58 @@
+#!/usr/bin/env python3
+"""
+Migration script to add ln1 and ln2 percentile columns to the nl43_status table.
+
+The NL-43 DOD response carries percentile slots LN1-LN5; the live SLM display
+(Terra-View) shows two of them (default L1/L10). This adds storage for the two
+surfaced slots. Run once per database to update existing schema.
+"""
+
+import sqlite3
+import sys
+from pathlib import Path
+
+DB_PATH = Path(__file__).parent / "data" / "slmm.db"
+
+
+def migrate():
+    """Add ln1 and ln2 columns to the nl43_status table."""
+
+    if not DB_PATH.exists():
+        print(f"Database not found at {DB_PATH}")
+        print("No migration needed - database will be created with new schema")
+        return
+
+    conn = sqlite3.connect(DB_PATH)
+    cursor = conn.cursor()
+
+    try:
+        cursor.execute("PRAGMA table_info(nl43_status)")
+        columns = [row[1] for row in cursor.fetchall()]
+
+        if "ln1" in columns and "ln2" in columns:
+            print("✓ ln1/ln2 columns already exist, no migration needed")
+            return
+
+        if "ln1" not in columns:
+            print("Adding ln1 column...")
+            cursor.execute("ALTER TABLE nl43_status ADD COLUMN ln1 TEXT")
+            print("✓ Added ln1 column")
+
+        if "ln2" not in columns:
+            print("Adding ln2 column...")
+            cursor.execute("ALTER TABLE nl43_status ADD COLUMN ln2 TEXT")
+            print("✓ Added ln2 column")
+
+        conn.commit()
+        print("\n✓ Migration completed successfully!")
+
+    except Exception as e:
+        conn.rollback()
+        print(f"✗ Migration failed: {e}", file=sys.stderr)
+        sys.exit(1)
+    finally:
+        conn.close()
+
+
+if __name__ == "__main__":
+    migrate()