fix(search): include reaction definitions in quick search

[VibhavSetlur]

Summary

• establish a schema-aware reaction-search contract: legacy Solr keeps flat stoichiometry/equation searches, while nested Solr parent-scopes result documents and block-joins child compound/participant_name matches
• quick search covers IDs, names, Equation (definition), status, EC numbers, aliases, pathways, notes, and stoichiometry; terms are escaped before generated wildcards
• harden findReactionsForCompound, URL encoding for query fields/sorts, and successful malformed-Solr-response handling without masking HTTP errors

Regression matrix

Decoded request assertions cover legacy and nested schemas; one/multiple quick terms with AND/OR; empty and intentional wildcard queries; prefix threshold; special-character/space escaping; Equation compound ID/name lookup; parent scoping; explicit string/boolean/numeric filters and OR composition; filter + quick search; queryColumn; direct query; pagination/sort/visible fields; schema detection/cache/failure; endpoint routing; and preserved compound batch behavior.

Live reproduction

Manual unauthenticated probes on 2026-09-08: staging.modelseed.org/solr/reactions_staging rejects doc_type (HTTP 400), proving the legacy path; modelseed.org/solr/reactions_staging accepts parent doc_type:reaction and the established {!parent ... doc_type:stoichiometry ...} join (HTTP 200). Browser/Vitest live integration is CORS-blocked (403 OPTIONS), so contract coverage is deterministic request-level tests.

Verification

• npx vitest run tests/unit/api/biochemStoichiometry.test.ts tests/unit/api/biochem.test.ts tests/unit/api/solrSchema.test.ts
• npm run lint
• npx tsc --noEmit
• npm run test:run
• npm run build
• npm audit --omit=dev --audit-level=high
• git diff --check

[VibhavSetlur]

Hardened after full reaction-search audit in be416cc. The PR description now records the complete decoded-request regression matrix and live schema probes (staging legacy vs production nested), plus the browser CORS limitation and deterministic test coverage.