## Why
The five API-key OpenBanking "connect" controllers — Binance, Bitpanda,
Coinbase, Indexa Capital and Interactive Brokers — each carried a
~60-line `store()` that was near-identical: subscription gate →
credential validation → `Bank::firstOrCreate` → create the
`BankingConnection` (Pending) → update it to `AwaitingMapping` with
pending accounts → auto-map during onboarding or redirect to mapping.
Any change to that flow, or a bug in it, had to be made five times.
## What
Extract the shared flow into a small class hierarchy, so each controller
declares only what actually varies per provider.
- **`OpenBankingConnectController`** (abstract) owns the whole flow in a
`connect()` template method, with per-provider extension points:
`provider()`, `providerName()`, `bankLogo()`, `aspspCountry()`,
`fetchProviderData()`, `credentialErrorMessage()`,
`buildPendingAccounts()`, and an optional `emptyProviderDataMessage()`
guard.
- **`CryptoPortfolioConnectController`** (abstract, extends the above)
implements the two hooks the crypto providers share: `aspspCountry()`
(from the request) and the single "Crypto Portfolio"
`buildPendingAccounts()` (uid derived from the provider enum value, so
the generated uids are unchanged).
- The five controllers shrink to their genuine differences (client,
names, logo, error copy, and — for IB — the Flex error mapping and
empty-statement guard).
Net **−110 lines** across the five `store()` methods, and the connection
lifecycle now lives in one place.
## Behavior
No functional change. The credential-failure warning log is now a single
structured message with a `provider` key instead of five free-text
variants (the only observable difference; HTTP responses are
byte-for-byte identical). Verified by the full suite: **1869 passing, 0
failing** (`--exclude-testsuite=Browser`); `pint --test`, `format` and
`lint` clean.
## Review-driven follow-up commits
Two review agents (architecture/duplication/coverage, and
behavior/regressions) ran against the first commit. Applied, each as its
own commit:
- Finished the crypto dedup via the intermediate base (the reviewers
flagged the still-duplicated crypto hooks).
- Dropped the over-engineered per-provider
`validationFailureLogMessage()` hook in favor of a structured base log.
- Added the missing test for the Interactive Brokers empty-statement
guard (the only conditional hook, previously unexercised): asserts 422 +
NAV-section message, no connection row, and no warning logged.
## Deliberately out of scope
- **Wise** is left as-is: it builds pending accounts mid-flow (needs the
client), creates the connection in one step, and has its own
empty-portfolio guard — it does not fit this template.
- **Pre-existing** (not introduced here, noted by review):
`Bank::firstOrCreate` returns an existing bank without refreshing its
logo, so `aspsp_logo` can copy a stale/null value. Worth a separate fix.