feat(router): add blocklist count and lookup endpoints

[ayush22667]

Type of Change

• Bugfix
• New feature
• Enhancement
• Refactoring
• Dependency updates
• Documentation
• CI/CD

Description

Base branch is feat/blocklist-card-bin-6-10, not main. This stacks on that branch's 6-10
digit BIN work and profile scoping, and should be merged after it.

Two read-only endpoints on the profile-scoped blocklist:

GET /blocklist/count?data_kind=<kind> returns

{ "data_kind": "card_bin", "total_count": 16, "counts_by_length": { "6": 12, "8": 3, "10": 1 } }

counts_by_length buckets by BIN digit length, computed in Postgres with
GROUP BY length(fingerprint_id) rather than paging every row (and its metadata blob) into the
app to count them.

GET /blocklist/lookup?data=<value> returns { "data": "411111", "blocked": true } - one yes/no
check for a single value, across every data_kind.

Both resolve the business profile exactly as add/delete already do, through
get_profile_id_from_business_details: X-Profile-Id when present, otherwise the merchant's
default_profile, otherwise IR_04. That also validates the profile belongs to the caller's
merchant, so one merchant cannot count or probe another's entries.

Two supporting changes:

• common_utils::types::BlocklistLookupData, a LengthString<20, 1> newtype bounding the lookup
  value at the API boundary. 20 is the longest a fingerprint_id can legitimately be - a card BIN is
  at most 10 digits, and a locker fingerprint id is a 20-character nano id. Validating in the type
  rather than in core means a future caller cannot skip it.
• expand_data_kinds in diesel_models, collapsing the CardBin -> [CardBin, ExtendedCardBin]
  expansion that was copy-pasted at six call sites in that file.

Additional Changes

• This PR modifies the API contract
• This PR modifies the database schema
• This PR modifies application configuration/environment variables

Two additive endpoints; no existing request or response shape changes, no schema change, no config
change. Both new routes sit inside the existing #[cfg(all(feature = "olap", feature = "v1"))]
blocklist scope, so there is no v2 surface.

Motivation and Context

GET /blocklist pages full rows, which is the only way to read the blocklist today. Answering "how
many entries do I have, and of what BIN lengths?" means paging everything and counting client-side,
and there is no way at all to ask "is this one value blocked?" without scanning. Both are cheap
questions that deserve cheap answers, and counts_by_length in particular is what makes the 6-10
digit BIN work legible to a merchant.

Linked Issues

• Issue: https://github.com/juspay/hyperswitch-cloud/issues/22992

How did you test it?

Compile-verified under v1: cargo check passes for common_utils, api_models, diesel_models,
router and openapi; cargo +nightly fmt clean; no lint warnings from the new code.

Postman requests covering both endpoints are staged in the Blocklist Profile Scoping folder
(13. Count blocked BINs, 14. Look up whether a BIN is blocked), asserting status, that
counts_by_length sums to total_count, and that a BIN blocked under one profile reports
blocked: true for that profile.

Not yet done, and worth a reviewer's attention before merge:

• The Postman requests have not been executed against a running server - their assertions are derived
  from the response types, not observed output.
• just check_v2, just clippy and just clippy_v2 have not been run. common_utils is touched
  and feature-gated, so v2 is the one to check.

Checklist

• I formatted the code cargo +nightly fmt --all
• I addressed lints thrown by cargo clippy
• I reviewed the submitted code
• I added unit tests for my changes where possible

[semanticdiff-com]

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Changed Files

File	Status
crates/common_utils/src/types.rs	17% smaller
crates/diesel_models/src/query/blocklist.rs	14% smaller
crates/openapi/src/openapi.rs	7% smaller
api-reference/v1/openapi_spec_v1.json	0% smaller
crates/api_models/src/blocklist.rs	0% smaller
crates/common_utils/src/consts.rs	0% smaller
crates/openapi/src/routes/blocklist.rs	0% smaller
crates/router/src/core/blocklist.rs	0% smaller
crates/router/src/core/blocklist/utils.rs	0% smaller
crates/router/src/db/blocklist.rs	0% smaller
crates/router/src/routes/app.rs	0% smaller
crates/router/src/routes/blocklist.rs	0% smaller
crates/router/src/routes/lock_utils.rs	0% smaller
crates/router_env/src/logger/types.rs	0% smaller