Parse transferable days from FK instead of deriving them

The scraper never read "överlåtbara dagar" from Försäkringskassan. It only
visited ansok-och-planera-foraldrapenning#/valjdagar and derived the
reserved/transferable split in build_snapshot, assuming transferable days
are spent before reserved ones. On real data that gave 49 for the user and
0 for the partner where FK states 129 and 71.

The assumption cannot be repaired: reserved-first, transferable-first,
proportional and cap-based models were all checked against real figures and
none reproduces FK's accounting (reserved-first fits the partner but is 10
days off for the user). FK publishes the real numbers per parent per tier on
the min-foraldrapenning page, which the scraper had never visited.

- Scrape the "Dagar ni kan föra över" panel after the valjdagar extraction,
  summing sjukpenningnivå + lägstanivå per parent. The totals are not
  literals on the page. Parse only direct-child <p> elements: the first
  group embeds a tooltip with decoy "45 dagar"/"90 dagar" text.
- build_snapshot accepts the reported value and derives reserved days from
  it; the old arithmetic remains only as a fallback. An implausible FK value
  degrades to that fallback rather than failing the fetch.
- Record provenance in transferable_days_reported (migration 006) and badge
  derived values as estimates in the dashboard breakdown. Drop the footnote's
  claim that at most 150 days are transferable — real data contradicts it as
  a per-family figure.
- Select the child's section by name when FK lists several; never guess.

Verified against a live BankID scrape: scraped 240/101/139 with 129
transferable, deduced partner 240/169/71 with 71, both flagged as reported.

Incidental fixes found along the way:

- The fetch router never forwarded the partner's transferable figure to
  persist_partner_deduction, so the partner's stored snapshot would have kept
  the flawed split even once the parse landed.
- 'deduced' snapshots were labelled "Manually entered" by a two-way ternary
  over a three-value union. Replaced with a compiler-checked exhaustive map.
- Alembic resolved its database from alembic.ini alone, ignoring
  APP_SQLITE_PATH, so migrations silently targeted the developer's real
  database even when pointed elsewhere. env.py now resolves it, preferring
  -x sqlalchemy.url, then a real APP_SQLITE_PATH, then the ini value.
- backend/captures/ was not ignored: the root pattern was anchored as
  /captures/ despite a comment saying scraper dumps must never be tracked.
- CLAUDE.md quoted test counts and coverage percentages that had gone stale,
  which made a correct verification report look suspect. Gate thresholds kept.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DXPBfr1v7F71t6QcbHCaaT

backend/migrations/env.py

@@ -7,20 +7,49 @@ layer stays independent of any Python model objects.
 from __future__ import annotations
 
 import asyncio
+import logging
 from logging.config import fileConfig
 from typing import Any
 
 from alembic import context
 
+from migrations.url_resolution import coerce_sqlite_async, resolve_database_url
+
 # Load the alembic.ini logging config without disabling existing loggers —
 # when running inside the FastAPI app the app's own loggers must not be reset.
 if context.config.config_file_name is not None:
     fileConfig(context.config.config_file_name, disable_existing_loggers=False)
 
+logger = logging.getLogger("alembic.env")
+
+
+def _resolve_url() -> str:
+    """Resolve the database URL for this migration run.
+
+    This is the SINGLE place both the offline and online paths get their URL
+    from — `alembic.ini`'s `sqlalchemy.url` is deliberately never read
+    directly anywhere else, so Alembic can never silently target a different
+    database than the one the running app actually uses.
+
+    The actual resolution order/logic lives in `migrations.url_resolution`
+    (kept separate so it is unit-testable without an active Alembic
+    context); this just wires Alembic's `-x` args and ini value into it.
+    """
+    x_args = context.get_x_argument(as_dictionary=True)
+    ini_url = context.config.get_main_option("sqlalchemy.url")
+    url = resolve_database_url(x_args, ini_url)
+    if not url:
+        raise RuntimeError(
+            "Could not resolve a database URL: no -x sqlalchemy.url, no "
+            "APP_SQLITE_PATH-derived setting, and no alembic.ini sqlalchemy.url."
+        )
+    return url
+
 
 def run_migrations_offline() -> None:
     """Emit SQL to stdout (used by `alembic upgrade --sql`)."""
-    url = context.config.get_main_option("sqlalchemy.url")
+    url = _resolve_url()
+    logger.info("Resolved database URL (offline mode): %s", url)
     context.configure(
         url=url,
         target_metadata=None,
@@ -41,10 +70,8 @@ async def run_migrations_online() -> None:
     """Run migrations against a live DB connection."""
     from sqlalchemy.ext.asyncio import create_async_engine
 
-    url = context.config.get_main_option("sqlalchemy.url")
-    # Coerce sqlite:// → sqlite+aiosqlite:// for async support.
-    if url and url.startswith("sqlite:///"):
-        url = url.replace("sqlite:///", "sqlite+aiosqlite:///", 1)
+    url = coerce_sqlite_async(_resolve_url())
+    logger.info("Resolved database URL (online mode): %s", url)
 
     connectable = create_async_engine(url)
     async with connectable.connect() as connection: