feat: add batch mode query endpoint

[dragonee]

Context

The only lookup endpoint today is GET /api/whose-name/query, which resolves exactly one {u, s, q} triple per request. Clients that need to reconcile many identities at once (e.g. a whole Slack channel against Jira) had to fire one HTTP request per lookup.

This adds a batch endpoint that accepts many queries in a single authenticated request, reusing the existing domain, Sanctum auth, and the per-request YamlFileRepository cache — so a batch costs ~one file read regardless of size.

API contract

POST /api/whose-name/query/batch (inside the existing auth:sanctum + ability:whose-name group)

Request

{"queries": [{"u":"test@example.org","s":"jira","q":"slack"}, ...]}

Response — a lean, index-correlated array in request order (null = no match):

[{"username":"U123456"},{"username":null}]

Status codes

• 200 OK — every query resolved to a username
• 207 Multi-Status — at least one query returned null (partial/total misses)
• 422 Unprocessable Entity — malformed body (strict validation: 1–100 items, each u/s/q required|string)

Changes

• Domain — QueryService::whatAreTheNamesOf() loops the existing whatIsTheNameOf(), keeping iteration/ordering in the domain layer (framework stays a client of the domain).
• Route — thin closure mapping u/s/q → domain and selecting 200/207.
• Tests — domain (Mockery) tests for order/partial-null/empty; application feature tests for 200/207/422.
• Docs — README "Batch query" section + an ADL recording the 207-vs-404 and lean-array decisions.

No DB/migration/binding changes; repository and interface untouched.

Verification

• ./vendor/bin/sail test --without-tty — 24 passed, 1 pre-existing skip; all new domain and endpoint tests green.
• Live curl against the booted app with a real Sanctum token confirmed 207 (mixed), 200 (all resolved), and 422 (malformed).

🤖 Generated with Claude Code