Add recurring transaction detection, subscriptions page, and UK tax reporting

- Recurring service: auto-detects direct debits/subscriptions from CSV imports
  using frequency analysis; manual toggle in transaction detail drawer
- Subscriptions page (/subscriptions): groups recurring payments with monthly
  cost equivalents, next-payment badges, and re-scan trigger
- UK Tax page (/tax): payslips/P60 entry, income tax + NI + CGT + dividend tax
  calculations, configurable rate tables per tax year (pre-seeded 2024/25 and
  2025/26), editable in-app so Budget changes need no rebuild
- Migration 0006: tax_rate_configs, tax_profiles, payslips, manual_cgt_disposals
  with RLS; seeds 2025/2026 rate configs for existing users
- Chart tooltip fix: all Recharts tooltips now use TOOLTIP_STYLE constant so
  they render correctly across all dark/light themes

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/schemas/tax.py

@@ -0,0 +1,215 @@
+import uuid
+from datetime import date as DateType, datetime
+from decimal import Decimal
+from typing import Any
+
+from pydantic import BaseModel, Field
+
+
+# ---------------------------------------------------------------------------
+# Tax rate config
+# ---------------------------------------------------------------------------
+
+class TaxRateConfigUpdate(BaseModel):
+    """PUT /tax/rate-configs/{tax_year} — pass only the rate types you want to upsert."""
+    income_tax: dict[str, Any] | None = None
+    ni: dict[str, Any] | None = None
+    cgt: dict[str, Any] | None = None
+    dividend: dict[str, Any] | None = None
+
+
+class TaxRateConfigResponse(BaseModel):
+    tax_year: int
+    rates: dict[str, Any]
+    updated_at: str
+
+
+# ---------------------------------------------------------------------------
+# Tax profile
+# ---------------------------------------------------------------------------
+
+class TaxProfileCreate(BaseModel):
+    tax_code: str = Field(default="1257L", min_length=1, max_length=20)
+    employer_name: str | None = Field(default=None, max_length=200)
+    is_cumulative: bool = True
+
+
+class TaxProfileResponse(BaseModel):
+    id: uuid.UUID
+    tax_year: int
+    tax_code: str
+    employer_name: str | None
+    is_cumulative: bool
+    created_at: str
+    updated_at: str
+
+
+# ---------------------------------------------------------------------------
+# Payslips
+# ---------------------------------------------------------------------------
+
+class PayslipCreate(BaseModel):
+    period_month: int | None = Field(default=None, ge=1, le=12)
+    period_year: int = Field(..., ge=2000, le=2100)
+    gross_pay: Decimal = Field(..., ge=0)
+    income_tax_withheld: Decimal = Field(..., ge=0)
+    ni_withheld: Decimal = Field(..., ge=0)
+    net_pay: Decimal = Field(..., ge=0)
+    notes: str | None = None
+
+
+class PayslipUpdate(BaseModel):
+    period_month: int | None = Field(default=None, ge=1, le=12)
+    period_year: int | None = Field(default=None, ge=2000, le=2100)
+    gross_pay: Decimal | None = Field(default=None, ge=0)
+    income_tax_withheld: Decimal | None = Field(default=None, ge=0)
+    ni_withheld: Decimal | None = Field(default=None, ge=0)
+    net_pay: Decimal | None = Field(default=None, ge=0)
+    notes: str | None = None
+
+
+class PayslipResponse(BaseModel):
+    id: uuid.UUID
+    tax_profile_id: uuid.UUID
+    period_month: int | None
+    period_year: int
+    gross_pay: str
+    income_tax_withheld: str
+    ni_withheld: str
+    net_pay: str
+    is_p60: bool
+    notes: str | None
+    created_at: str
+
+
+class P60Entry(BaseModel):
+    gross_pay: Decimal = Field(..., ge=0)
+    income_tax_withheld: Decimal = Field(..., ge=0)
+    ni_withheld: Decimal = Field(..., ge=0)
+    net_pay: Decimal = Field(..., ge=0)
+
+
+# ---------------------------------------------------------------------------
+# Manual CGT disposals
+# ---------------------------------------------------------------------------
+
+class ManualDisposalCreate(BaseModel):
+    disposal_date: DateType
+    asset_description: str = Field(..., min_length=1, max_length=500)
+    proceeds: Decimal = Field(..., ge=0)
+    cost_basis: Decimal = Field(..., ge=0)
+    notes: str | None = None
+
+
+class ManualDisposalUpdate(BaseModel):
+    disposal_date: DateType | None = None
+    asset_description: str | None = Field(default=None, min_length=1, max_length=500)
+    proceeds: Decimal | None = Field(default=None, ge=0)
+    cost_basis: Decimal | None = Field(default=None, ge=0)
+    notes: str | None = None
+
+
+class ManualDisposalResponse(BaseModel):
+    id: uuid.UUID
+    tax_year: int
+    disposal_date: str
+    asset_description: str
+    proceeds: str
+    cost_basis: str
+    gain_loss: str
+    notes: str | None
+    created_at: str
+
+
+# ---------------------------------------------------------------------------
+# Tax report (nested)
+# ---------------------------------------------------------------------------
+
+class BandBreakdownItem(BaseModel):
+    rate: float
+    taxable: float
+    tax: float
+    from_: int | None = Field(default=None, alias="from")
+    to: int | None = None
+
+    model_config = {"populate_by_name": True}
+
+
+class IncomeTaxSummary(BaseModel):
+    personal_allowance: str
+    taxable_income: str
+    liability: str
+    band_breakdown: list[dict[str, Any]]
+    withheld: str
+    owed: str
+
+
+class NISummary(BaseModel):
+    liability: str
+    band_breakdown: list[dict[str, Any]]
+    withheld: str
+    owed: str
+
+
+class InvestmentDisposalItem(BaseModel):
+    date: str
+    asset: str
+    symbol: str
+    quantity: str
+    proceeds: str
+    cost_basis: str
+    fees: str
+    gain_loss: str
+
+
+class CGTSummary(BaseModel):
+    gross_gain: str
+    exempt: str
+    taxable_gain: str
+    liability: str
+    band_breakdown: list[dict[str, Any]]
+    investment_disposals: list[dict[str, Any]]
+    manual_disposals: list[dict[str, Any]]
+    total_gain: str
+
+
+class DividendTransactionItem(BaseModel):
+    date: str
+    asset: str
+    symbol: str
+    amount: str
+
+
+class DividendSummary(BaseModel):
+    gross_dividends: str
+    allowance: str
+    taxable_dividends: str
+    liability: str
+    band_breakdown: list[dict[str, Any]]
+    dividend_transactions: list[dict[str, Any]]
+
+
+class TaxReportSummary(BaseModel):
+    total_liability: str
+    total_withheld: str
+    net_owed: str
+    overpaid: bool
+
+
+class IncomeSummary(BaseModel):
+    gross_income: str
+    income_tax_withheld: str
+    ni_withheld: str
+    payslips: list[dict[str, Any]]
+
+
+class TaxReportResponse(BaseModel):
+    tax_year: int
+    tax_year_display: str
+    profile: dict[str, Any] | None
+    income: IncomeSummary
+    income_tax: IncomeTaxSummary
+    ni: NISummary
+    cgt: CGTSummary
+    dividends: DividendSummary
+    summary: TaxReportSummary