docs(releases): v0.6.0 — describe inline + canonical-named queries (MR-656)

Extend the v0.6.0 release notes to cover the third piece of work landing
alongside the graph terminology rename and multi-graph server mode:
canonical-named `POST /query` and `POST /mutate` endpoints, the CLI's
new `-e/--query-string` flag, the top-level promotion of `lint` /
`check`, and the three-channel deprecation signal on `/read` and
`/change` (OpenAPI `deprecated: true` + RFC 9745 + RFC 8288).

Additions:

* Top blurb: "Two pieces" -> "Three pieces" with a bullet describing
  the rename + inline flow.
* Breaking Changes: new "Query / mutation rename" subsection covering
  the `ChangeRequest` field rename (with the back-compat serde aliases
  and the CLI's `legacy_change_request_body` byte-stable wire helper)
  and the `omnigraph query lint` -> `omnigraph lint` move.
* New: 5 bullets — the two endpoints, the CLI subcommands, the `-e`
  flag, the deprecation signal channels, the widened `aliases.<name>.command`
  vocabulary.
* User Impact: one bullet making explicit that the rename is cosmetic
  on the client side and migration is voluntary.
* Documentation: pointers to the updated `server.md` / `cli.md` /
  `cli-reference.md` and the new `docs/dev/rfc-001-queries-envelope-mcp.md`.

+15/-1 lines. `./scripts/check-agents-md.sh` clean.

docs/releases/v0.6.0.md

@@ -1,9 +1,10 @@
 # Omnigraph v0.6.0
 
-Two pieces of work land in this release:
+Three pieces of work land in this release:
 
 1. The **graph terminology rename** (renamed `Repo` → `Graph` across the Cedar resource model, policy API, and query-lint schema source).
 2. **Multi-graph server mode** — one `omnigraph-server` process can now serve 1–10 graphs concurrently behind cluster routes (`/graphs/{graph_id}/...`), with per-graph and server-level Cedar policy, read-only `GET /graphs` enumeration, and CLI parity (`omnigraph graphs list`).
+3. **Inline + canonical-named queries and mutations.** New `POST /query` and `POST /mutate` endpoints pair with the CLI's new `-e/--query-string` flag for ad-hoc execution without a temp file. `POST /read` and `POST /change` continue serving indefinitely as deprecated aliases that carry RFC 9745 `Deprecation: true` and RFC 8288 `Link: </successor>; rel="successor-version"` response headers, plus `deprecated: true` in `openapi.json`. Same canonicalization on the CLI: `omnigraph query`, `omnigraph mutate`, and top-level `omnigraph lint` / `omnigraph check` replace `omnigraph read`, `omnigraph change`, and the nested `omnigraph query lint` / `omnigraph query check`. Every deprecated spelling remains a `visible_alias` that warns to stderr once per invocation.
 
 Runtime add/remove (`POST /graphs`, `DELETE /graphs/{id}`, `omnigraph graphs create`) is **not** in v0.6.0. Operators add or remove graphs by editing `omnigraph.yaml` and restarting. The first cut of `POST /graphs` shipped behind an atomic-YAML-rewrite design that we pulled before release once its concurrency guarantees were challenged (flock-on-renamed-inode race, duplicate-check outside the critical section, and an init-cleanup path that could destroy an existing graph's schema on re-init). The correct fix is a Lance-style cluster catalog (reserve → init → publish with recovery sidecars); that work is deferred.
 
@@ -31,6 +32,11 @@ Runtime add/remove (`POST /graphs`, `DELETE /graphs/{id}`, `omnigraph graphs cre
 - **Tokens without policy default-deny non-read actions.** Existing authenticated deployments that relied on writes or admin routes without Cedar policy must add policy rules for those actions.
 - **`GET /graphs` requires `server.policy.file` in every runtime state.** Even `--unauthenticated` mode keeps server topology closed until the operator explicitly authorizes `graph_list`.
 
+### Query / mutation rename
+
+- **`ChangeRequest` field rename**: `query_source` → `query`, `query_name` → `name`. Both legacy names continue to deserialize via `#[serde(alias = "...")]`, so existing clients sending the old JSON keys keep working. CLI remote calls against `/change` still emit the legacy keys verbatim through the `legacy_change_request_body` helper so a newer CLI talking to an older server keeps working byte-for-byte.
+- **CLI `omnigraph query lint` / `omnigraph query check`** are now top-level `omnigraph lint` / `omnigraph check`. The legacy invocations remain as argv-level shims that rewrite to the canonical form and print a one-line deprecation warning to stderr.
+
 ## New
 
 - **Multi-graph mode**. Invoke with `omnigraph-server --config omnigraph.yaml` where the YAML has a non-empty `graphs:` map and no single-mode selector (no `server.graph`, no CLI `<URI>` or `--target`). At startup the server opens every configured graph in parallel (bounded concurrency, fail-fast).
@@ -41,6 +47,11 @@ Runtime add/remove (`POST /graphs`, `DELETE /graphs/{id}`, `omnigraph graphs cre
 - **Server-level Cedar policy**. `server.policy.file` in the config governs the `graph_list` action on `Omnigraph::Server::"root"`. Required to expose `GET /graphs` in every runtime state — without a server policy the default-deny posture rejects `graph_list`, including in `--unauthenticated` mode.
 - **Cedar action vocabulary**: `graph_list` (server-scoped). Runtime `graph_create` / `graph_delete` are reserved but not shipped — see "Deferred."
 - **Canonical graph URI identity.** Server startup normalizes graph root URIs before registry insertion and response output, so aliases such as `/tmp/g`, `/tmp/g/`, and `file:///tmp/g` cannot register as distinct graphs that actually share one Lance root.
+- **`POST /query`** and **`POST /mutate`**. Canonical inline endpoints. `/query` rejects mutations with a typed 400 (the D2 rule lives at the URL — read-only contract enforced before execution); body uses the clean `{ query, name, params, branch, snapshot }` shape. `/mutate` accepts the same shape for mutations. Both available in single mode and per-graph multi mode (`/graphs/{id}/query`, `/graphs/{id}/mutate`). Internal call sites share two helpers (`run_query`, `run_mutate`) that take decoupled args, not request bodies — the seam MR-969's future stored-query handler plugs into.
+- **CLI `omnigraph query` / `omnigraph mutate`** as top-level canonical subcommands. Pairs with new top-level **`omnigraph lint` (alias `check`)** so query validation no longer sits under `omnigraph query`.
+- **CLI `-e, --query-string <GQ>`** on both `omnigraph query` and `omnigraph mutate`. 3-way mutex with `--query <path>` and `--alias <name>` — exactly one is required. Empty string rejected. Suits ad-hoc exploration, REPL workflows, and agent tool-use without temp files.
+- **Three-channel deprecation signal on `/read` and `/change`**: OpenAPI `deprecated: true` on the operation (every codegen flags the generated SDK method), RFC 9745 `Deprecation: true` response header, and RFC 8288 `Link: </query>; rel="successor-version"` (or `</mutate>`) response header. Auto-discoverable; no SDK breakage.
+- **`omnigraph.yaml` `aliases.<name>.command`** now accepts `query` and `mutate` as canonical values alongside the legacy `read` and `change`. The internal `AliasCommand` enum retains the legacy variant names so serialized configs stay byte-stable.
 
 ## Configuration
 
@@ -79,6 +90,7 @@ graphs:
 - **Cluster routes are breaking for client SDKs targeting multi mode.** Generated clients from previous v0.5.0 OpenAPI specs will hit 404 on flat paths against a multi-mode server. Regenerate against the v0.6.0 `openapi.json`.
 - **Supported YAML policy authoring is unchanged.** The Cedar `Omnigraph::Graph` and `Omnigraph::Server` entities are internally generated by `compile_policy_source` — operator YAML only references actions and groups.
 - **Operators with unsupported raw Cedar policy files** should update `Omnigraph::Repo` resource references to `Omnigraph::Graph`.
+- **Endpoint and CLI rename is cosmetic on the client side.** Existing callers on `/read`, `/change`, `omnigraph read`, `omnigraph change`, and `omnigraph query lint` keep working — they pick up the `Deprecation` + `Link` headers (or stderr deprecation warning on the CLI) so SDKs and proxies can surface the successor name automatically. New integrations should target the canonical names. ChangeRequest field names migrate at the caller's pace — both `query_source`/`query_name` and `query`/`name` accepted indefinitely.
 
 ## Migration: single → multi
 
@@ -114,6 +126,8 @@ To add a new graph after rollout: stop the server, append a new `graphs.<id>` en
 - Public docs, CLI help, examples, server docs, and test helpers now consistently use "graph" for the OmniGraph data artifact.
 - GitHub/source repository terminology remains spelled out as "repository" where needed.
 - New: `docs/user/cli.md` documents `omnigraph graphs list`; `docs/user/server.md` documents the multi-graph mode and the cluster route convention; `docs/user/policy.md` documents the per-graph vs server-scoped action distinction.
+- New: `docs/user/server.md` documents `POST /query` / `POST /mutate` and the three-channel deprecation signal on `/read` / `/change`. `docs/user/cli.md` documents the `-e/--query-string` flag with examples. `docs/user/cli-reference.md` shows the canonical CLI verbs (`query`, `mutate`, `lint`, `check`) with legacy spellings as visible aliases.
+- New: `docs/dev/rfc-001-queries-envelope-mcp.md` is the cross-cutting design doc for the inline / stored query work that started landing in this release. It sequences the v0.6.x patch series (request/response envelope hardening) and the v0.7.0 stored-query + MCP work.
 
 ## Test coverage