Let imports opt out of AI classification

Classification preferences gains "Classify newly imported transactions with
AI", stored as classify_on_import in config.toml and on by default, so existing
configurations keep their behaviour. It covers CSV imports and bank
synchronization alike.

With it off, no import path contacts the provider: classification falls to the
new provider-free rules path, where an opted-in merchant rule still applies its
category and tags, an alias match still attaches its merchant, and everything
else arrives on the editable fallback without a provenance error that would
suggest the provider had failed. Analyse remains available on demand.

README.md

@@ -375,6 +375,8 @@ For administrator-managed startup configuration, `OPENROUTER_API_KEY` in the ser
 
 Bank synchronization and recognized N26, ING, and Kontist CSV imports do **not** require this key; only mapping an unrecognized CSV layout does. Without AI, explicit merchant-default rules still work; unresolved transactions remain unclassified and editable.
 
+**Classify newly imported transactions with AI** under **Classification preferences** controls whether importing contacts the provider at all. It covers CSV imports and bank synchronization, is on by default, and is stored as `classify_on_import` in `config.toml`. With it off, no import makes a provider request: enabled merchant rules still classify, and everything else arrives unclassified and editable without a failure that would suggest the provider was unreachable. **AI classification → Analyse** still works on demand, so you can review a batch deliberately instead of on every import.
+
 Every AI classification requests `provider.data_collection = "deny"`, `provider.zdr = true`, and `provider.require_parameters = true`. Unsupported private routing fails rather than falling back to a less restrictive provider. Amount sharing is off by default. Keep OpenRouter account prompt logging disabled as well. Automatic redaction minimizes data; it is not a guarantee that arbitrary transaction prose is anonymous.
 
 Classification spaces request starts by at least **three seconds**, including successful requests, rather than sending a burst between 429s. This is a conservative application policy, not a published quota for every model. On HTTP 429, backoff starts at **15 seconds** and increases across consecutive failures; `Retry-After` seconds or HTTP dates can extend the wait. Successful retries retain the learned spacing (up to **30 seconds**) instead of immediately bursting again. Each operation makes at most **four attempts**, with at most **two minutes of automatic retry waiting**, preserving the same model, sanitized prompt, and privacy controls. Imports and previews share this pacing and cooldown. Long or exhausted limits leave records unclassified with a retry-time error; local merchant rules still work. After the cooldown, run **AI classification → Analyse** again for previously failed records—repeating a bank import does not reclassify existing transactions.