Replace the generic records table with a lean join_leads table

records was a leads table wearing a generic name. It carried display_name /
email / phone, which only mean anything for a lead, plus status / assigned_to /
notes, which were a guess at an outreach process that has not been designed.
Contacting a family is one-to-many, so three columns on the lead row was always
the wrong shape for it.

join_leads is one row per /join submission with one column per form field, two
timestamps, and payload holding the submission verbatim. Outreach gets its own
table when the process is actually known.

Also splits heard_from from heard_from_detail. app.py folded source_place /
source_other into a composed "Other: ..." string and threw the raw answer away,
which is the half that tells you which daycare the lead came from. The composed
value is still built for the Sheet and the ntfy push.

admin API: /records -> /leads, and PATCH is gone since a lead now has nothing
mutable on it. mirrors and meta are unchanged.

app/app.py

@@ -623,10 +623,14 @@ def pipeline_notify(rec, sheet_error=None):
 def join_post(parent_name: str = Form(...), email: str = Form(...), phone: str = Form(""),
               children: str = Form(""), interested_in: str = Form(""), source: str = Form(""),
               source_place: str = Form(""), source_other: str = Form(""), message: str = Form("")):
+    heard_from = source.strip()
+    heard_from_detail = ""
     if source == "Other school or daycare" and source_place.strip():
-        source = "School/Daycare: " + source_place.strip()
+        heard_from_detail = source_place.strip()
+        source = "School/Daycare: " + heard_from_detail
     elif source == "Other" and source_other.strip():
-        source = "Other: " + source_other.strip()
+        heard_from_detail = source_other.strip()
+        source = "Other: " + heard_from_detail
     rec = {"ts": datetime.datetime.now().isoformat(timespec="seconds"),
            "parent_name": parent_name.strip(), "email": email.strip(), "phone": phone.strip(),
            "children": children.strip() or "(not given)",
@@ -642,11 +646,11 @@ def join_post(parent_name: str = Form(...), email: str = Form(...), phone: str =
     # against the record so a failure is replayable instead of just shouted.
     record_id = None
     try:
-        record_id = store.insert_record(
-            kind="join_lead", source=rec["source"], payload=rec,
-            unit=store.unit_of(rec["interested_in"]),
-            display_name=rec["parent_name"], email=rec["email"],
-            phone=rec["phone"], created_at=rec["ts"])
+        record_id = store.insert_lead(
+            parent_name=rec["parent_name"], email=rec["email"], phone=rec["phone"],
+            interested_in=rec["interested_in"], children=rec["children"],
+            heard_from=heard_from, heard_from_detail=heard_from_detail,
+            message=rec["message"], payload=rec, submitted_at=rec["ts"])
     except Exception as e:
         print("STORE WRITE FAILED for %s <%s>: %s" % (rec["parent_name"], rec["email"], e), flush=True)
     sheet_error = None