v0.4.5: ACP schema 0.4.5 alignment

Tracks ACP schema 0.4.5. The only Go-visible change is a rename of the session/set_model method constant to align with the schema's naming; the wire protocol is unchanged.

Changed

• Schema bumped to 0.4.5 with regenerated bindings (#1 by @ThomasK33).
• The generated agent method constant was renamed from AgentMethodModelSelect to AgentMethodSessionSetModel so its identifier matches the session_set_model schema key. The underlying JSON-RPC method string is still "session/set_model", so peers on the wire are unaffected.
• Schema source and documentation links now point at the protocol's new home, agentclientprotocol/agent-client-protocol (previously zed-industries/agent-client-protocol). This affects the Makefile fetch URLs and README.md / RELEASING.md references.

AgentExperimental.SetSessionModel and ClientSideConnection.SetSessionModel continue to work as before — only the constant identifier changed.

Breaking Changes

Callers that referenced the constant directly need a one-line rename:

// before
conn.SendRequest(ctx, acp.AgentMethodModelSelect, params)

// after
conn.SendRequest(ctx, acp.AgentMethodSessionSetModel, params)

No changes are required for code that calls SetSessionModel through the typed client/agent interfaces.

New Contributors

• @ThomasK33 made their first contribution in #1

Full Changelog: v0.4.4...v0.4.5