v0.50.0: every active capability names an input and an output schema that match its routes (WS-C task 4): 162 gaps to 0, 313 new request, result and record schemas with fixtures, older references corrected; capability-schema test; ADR-028 expand/migrate/contract; search query and write schemas

ddiff --git a/CHANGELOG.md b/CHANGELOG.md
iindex b29926c8..63bde56a 100644
---- a/CHANGELOG.md
++++ b/CHANGELOG.md
@@@ -4,7 +4,7 @@ All notable changes to `openvibe-contracts`. Releases are git tags (`vX.Y.Z`) th
  from `https://codeload.github.com/OpenVibers/OpenVibe.Contracts/tar.gz/refs/tags/<tag>`. Before v0.30.0,
  the notes were in the tag and commit messages (`git tag -n1`).
  
--## Unreleased
++## 0.50.0 — 2026-09-25
  
  Capability schemas (roadmap WS-C task 4), starting with Search: **`search.query@1`** (the query string of `GET /api/v1/search` and `/suggest`: q, owner, type, lang, facets, limit, cursor, `facet.<key>`), **`search.query-result@1`** (a page of hits the caller may see, `next_cursor`, facet counts; never an ACL or a total) and **`search.write-result@1`** (`PUT /api/v1/documents/…`: applied or unchanged; stale and conflicting revisions are 409 problems). `search.query.run` and `search.query.delegate` name the first two; `search.document.write` names the third as its output. Fixtures for each. Two conventions so every capability can name schemas: **`common.no-body@1`** (a request whose parameters are the path and query) and **`common.binary@1`** (a response of bytes); **`media.file-upload@1`** is the multipart body of `POST /api/v1/:app/files`. The Media and Tools capabilities name them. **A ratchet**: `test/capability-schemas.test.js` fails on an active capability without an input or output schema unless it is in `compatibility/capability-schema-gaps.json` (162 today), and on a listed gap that has been filled; the list only shrinks. Additive.
  
ddiff --git a/package-lock.json b/package-lock.json
iindex fa03876c..4353d88b 100644
---- a/package-lock.json
++++ b/package-lock.json
@@@ -1,12 +1,12 @@
  {
    "name": "openvibe-contracts",
--  "version": "0.49.0",
++  "version": "0.50.0",
    "lockfileVersion": 3,
    "requires": true,
    "packages": {
      "": {
        "name": "openvibe-contracts",
--      "version": "0.49.0",
++      "version": "0.50.0",
        "license": "AGPL-3.0-only",
        "dependencies": {
          "ajv": "^8.17.1",
ddiff --git a/package.json b/package.json
iindex 5c1a0758..f4b99c2c 100644
---- a/package.json
++++ b/package.json
@@@ -1,6 +1,6 @@
  {
    "name": "openvibe-contracts",
--  "version": "0.49.0",
++  "version": "0.50.0",
    "description": "Machine-readable contracts for the OpenVibe network: schemas, manifests, ids, error envelope, capability checks.",
    "main": "index.js",
    "types": "generated/typescript/index.d.ts",