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/url_resolution.py

@@ -0,0 +1,67 @@
+"""Pure database-URL resolution logic for Alembic migrations.
+
+Kept separate from `env.py` so it is importable and unit-testable on its own:
+`env.py` has import-time side effects tied to an active Alembic
+`MigrationContext` (it calls `alembic.context.config...` at module scope) and
+cannot be imported outside of an actual `alembic` invocation. This module has
+no such dependency — it only takes plain values in and returns plain values
+out.
+
+Resolution order implemented by `resolve_database_url` (first match wins):
+1. An explicit `-x sqlalchemy.url=...` argument — a documented way to point a
+   one-off Alembic run at a scratch database without touching the environment.
+2. `APP_SQLITE_PATH` read directly from `os.environ` — but only when it is
+   genuinely present and non-empty. This deliberately does NOT go through
+   `app.config.Settings`: `Settings.sqlite_path` has a default
+   (`"./foraldraledig.db"`), so a `Settings()` instance can never tell "the
+   env var was set to the default's value" apart from "the env var was never
+   set at all" — the default always wins, which made step 3 below dead code
+   and meant a `sqlalchemy.url` set programmatically on the Alembic `Config`
+   (e.g. `cfg.set_main_option(...)` in a test) was silently ignored in favour
+   of whatever `./foraldraledig.db` resolved to, including the developer's
+   real local database. Reading `os.environ` directly is the only way to
+   distinguish "explicitly set" from "defaulted".
+   Only the real `APP_SQLITE_PATH` environment variable counts here — a value
+   from an `.env` file is deliberately NOT treated as "explicitly set" (this
+   resolver never loads `.env`). `.env` is a developer convenience with
+   quietly-applied defaults, exactly the kind of implicit source that caused
+   this bug; requiring a real env var keeps "what database does this
+   migration run touch" answerable by looking at the process environment
+   alone, and it means an `.env` file can never silently retarget migrations
+   for anyone running Alembic (locally or in CI) who does not also have that
+   exact environment variable exported.
+3. The `sqlalchemy.url` value from `alembic.ini` — or from
+   `Config.set_main_option("sqlalchemy.url", ...)`, which is indistinguishable
+   from `alembic.ini` by the time it reaches `context.config.get_main_option`
+   — as the fallback when neither of the above applies.
+
+This is the single place that decides which database Alembic touches — never
+read `alembic.ini`'s `sqlalchemy.url` directly anywhere else, so migrations
+can never silently target a different database than the one the running app
+actually uses.
+"""
+
+from __future__ import annotations
+
+import os
+
+
+def resolve_database_url(x_args: dict[str, str], ini_url: str | None) -> str | None:
+    """Resolve the database URL from -x args, a real APP_SQLITE_PATH env var,
+    then the ini fallback."""
+    explicit_url = x_args.get("sqlalchemy.url")
+    if explicit_url:
+        return explicit_url
+
+    sqlite_path = os.environ.get("APP_SQLITE_PATH")
+    if sqlite_path:
+        return f"sqlite:///{sqlite_path}"
+
+    return ini_url
+
+
+def coerce_sqlite_async(url: str) -> str:
+    """sqlite:/// → sqlite+aiosqlite:/// so the async engine can use it."""
+    if url.startswith("sqlite:///"):
+        return url.replace("sqlite:///", "sqlite+aiosqlite:///", 1)
+    return url