feat(cli): configurable gRPC max receive message size

[lemonprogis]

Description

The CLI's gRPC client used gRPC's built-in 4 MiB cap on incoming unary messages, which is below what some control-plane responses (notably workflow run describe with many materials/policies) now produce. Hitting it failed the command with grpc: received message larger than max. Raising max_recv_msg_size on the control plane didn't help because that knob governs server-inbound, not the CLI's receive side.

Changes

• pkg/grpcconn now applies a bounded DefaultMaxRecvMsgSize of 32 MiB to all client connections, replacing gRPC's 4 MiB default.
• New grpcconn.WithMaxRecvMsgSize(int) option for explicit overrides.
• New CLI persistent flag --max-recv-msg-size, config key api-max-recv-msg-size, and env var CHAINLOOP_API_MAX_RECV_MSG_SIZE. 0 keeps the default.
• Wired through the control-plane and CAS dial sites in cmd/root.go and cmd/artifact.go.
• Regenerated CLI reference docs.

Server-side max_recv_msg_size (already exposed in control-plane config) and the new client-side flag are now symmetric, documented knobs.

Related to #3048

AI disclosure

Assisted by Claude Code.

[cubic-dev-ai]

No issues found across 5 files

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