whatif: live data refresh, inflation-adjusted spending, legend fix

Three follow-ups to the actualbudget integration:

**Always-fresh autofill.** Drop the one-shot `*AutoFilled` boolean
gates; replace with `nwUserEdited` / `spendingUserEdited` flags. Until
the user types into either field, every refetch (mount, window
focus) updates the form value. Once they edit, we leave it alone. A
small ↻ button next to each anchor input flips the edited flag back
off so the user can re-snap to live data on demand. React Query
configured with staleTime=0 + refetchOnMount='always' +
refetchOnWindowFocus=true so the cache never serves stale numbers.
NW provenance shows the snapshot date.

**Inflation-adjusted spending.** Backend now revalues each trailing
month's nominal pence forward to today's £ using monthly compounding
of `inflation_pct` (default 0.03 ≈ UK CPI 2024-26). Headline
`total_gbp` is the real-£ figure — matches the simulator's
real-GBP convention. Response also includes `nominal_total_gbp` and
`inflation_pct` for transparency. New /spending/annual?inflation_pct=
override param. 10/10 actualbudget tests pass.

**FanChart legend.** The bottom-anchored legend was overlapping the
x-axis label. Moved to top: 8 with itemGap=18 + type=scroll for
narrow viewports; bumped grid top→48 / bottom→56 + xAxis nameGap→28
so nothing collides.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

fire_planner/api/schemas.py

@@ -147,18 +147,28 @@ class SpendingMonth(BaseModel):
 class AnnualSpending(BaseModel):
     """Aggregated trailing-N-month spending pulled from actualbudget.
 
-    `total_gbp` is what we suggest as the "Annual spending" default in
-    the WhatIf form: the sum of all category groups across the trailing
-    window, *minus* whichever groups the caller asked to exclude
-    (default: investments/savings transfers, which aren't consumption).
+    `total_gbp` is the headline figure used as the "Annual spending"
+    default in the WhatIf form. It is **inflation-adjusted to today's
+    £** (each month's nominal pence revalued forward by
+    `inflation_pct` compounded monthly), matching the simulator's
+    real-£ convention.
+
+    `nominal_total_gbp` is the same window without inflation
+    adjustment — for transparency / comparison.
+
+    `raw_total_gbp` is the nominal sum *including* groups that were
+    excluded (e.g. investment transfers) — useful when you want to
+    see your full cash outflow.
     """
     months: int
     window_start: str  # "YYYY-MM" (oldest month included)
     window_end: str    # "YYYY-MM" (newest)
     excluded_groups: list[str]
-    total_gbp: Decimal               # the headline number
-    raw_total_gbp: Decimal           # before exclusions, for transparency
-    by_group_total_gbp: dict[str, Decimal]  # 12-mo group sums (incl. excluded)
+    inflation_pct: Decimal           # annual rate applied
+    total_gbp: Decimal               # inflation-adjusted, after exclusions
+    nominal_total_gbp: Decimal       # not adjusted, after exclusions
+    raw_total_gbp: Decimal           # nominal, before exclusions
+    by_group_total_gbp: dict[str, Decimal]  # nominal 12-mo group sums (incl. excluded)
     monthly: list[SpendingMonth]