[kit:ruby][axis:A] Bootstrap mint-ruby-self-contracts orchestrator

[TSavo]

Tracks the substrate-side conformance work for the ruby kit (Side A of the (A)/(B) split per #176).

Background

The ruby kit has an LSP plugin (PR #173) and an IR module, but no self-contracts orchestrator and no ruby slab with canonical contracts.

Scope

Tier 3 work. Bootstrap the orchestrator:

• Create implementations/ruby/lib/provekit/self_contracts.rb orchestrator
• Author the ruby slab with the canonical contracts
• RPC layer emitting proof-envelope to stdout under canonical --rpc lift-protocol framing
• Add ruby-self-contracts lift surface manifest at implementations/ruby/.provekit/lift/ruby-self-contracts/manifest.toml
• Update KIT_TABLE in implementations/rust/provekit-cli/src/cmd_mint.rs to route the ruby entry to the new surface
• Add a pinned-CID test in mint_kit_integration.rs

Acceptance

• make mint-ruby produces a content-meaningful contractSetCid
• provekit prove --kit=ruby exits 0 in CI
• Pinned-CID test passes

See also

• Parent: [kit:ruby] 4-component substrate coverage #156
• (A)/(B) framing: [bug] cmd_mint KIT_TABLE wires --kit=<lang> to generic-lifter surface, not self-contracts surface #176
• Tier 1 reference PRs: fix(cli): wire --kit=go to go-self-contracts surface (#176 Tier 1) #180, fix(cli): wire --kit=rust to walk self-contracts canonical contracts (#176 Tier 1) #183

[TSavo]

Ruby Side B (#210) landed via PR #226. This unblocks Ruby Side A. Dispatching an agent for it now.