Wire Idriç Ballotpedia client through ICU

[isomorphisms]

Boundary

Completes the page-one Ballotpedia API4 elections client in Idriç. Idriç owns argument validation, request meaning, environment lookup, typed JSON projection, and TSV rendering; ICU remains the only HTTP/TLS implementation.

Re-evaluation of the original holes

• Environment: Idriç #64 did merge environment_value : String → IO (Maybe String), including unset/empty distinction and invalid-name rejection. A later source-layout rewrite dropped it from the buildable _ tree, so Idriç #67 restores that exact narrow surface. CI pins the corresponding compiler integration commit.
• Caller headers and captured body: ICU #13's current head accepts checked repeatable -H values and writes the response body to stdout. The CLI invokes ICU with System.run, checks its exit status, and decodes the captured stdout. No second HTTP implementation is present.
• JSON: Language.JSON parses the body, following the working pattern already exercised by idric-cli Add CourtListener search through ICU #2. Ballotpedia then projects the JSON into typed Candidate values before rendering.

Request/response correction

The opened checkpoint used date= and a flat data.candidates fixture. Available Ballotpedia client implementations instead support:

• election_date=YYYY-MM-DD&page=1
• data.districts → races → candidates → person / party_affiliation

The fixture, decoder, and TSV columns now follow that nested shape.

Receipts

• focused request, header, typed decode, invalid-JSON, wrong-envelope, and TSV-cleaning checks
• deterministic end-to-end server receipt that verifies the exact request path, x-api-key, and Accept header, then proves ICU body capture, typed decoding, and exact TSV output
• missing and empty API-key behavior remains distinct
• existing Amazon and AbeBooks tests still pass

Genuinely remaining boundaries

• ICU #13 and the Idriç layout restoration (#67) are not yet merged dependencies
• ICU's executable interface carries header values in the child-process argument vector; a non-argv credential channel is still absent
• only page 1 is implemented; pagination is not
• the nested fixture is synthetic, and no paid live API receipt has been captured with an explicitly supplied key

Normal execution uses https://api4.ballotpedia.org/data/elections_by_state. BALLOTPEDIA_API_BASE exists only to make the deterministic receipt possible.