feat(handoff)!: delegate to rote guidance ids instead of rote skills

[roberts-pumpurs]

Rote 0.89.0 deletes its 15 companion skills and the rote-onboard plugin, so Play's 13 delegated actions, which load a rote skill by name, would hit a skill that no longer exists. The rote side is the stack ending in modiqo/rote#2768; ship both on the same day.

Before

references/controller/actions.yaml names a skill per delegated action (specialist: rote-flow-authoring). SKILL.md tells the agent to invoke instruction.specialist through the harness skill mechanism. handoff.py rejects any receipt whose executor.kind is not skill. The installer runs rote install skill --package '*' --force.

After

• Each delegated action names a guidance id (guidance: play/authoring, registry/org, gate/route, adapters/config, …). The controller projects instruction.guidance, and the agent runs rote guidance <id> in its shell and returns the declared receipt.
• Receipts carry executor: {kind: guidance, id, digest}. Verification requires the id to equal the packet owner and a sha256: digest from rote guidance <id> --json. The authentication event declares guidance_digest for the receipt Play builds itself.
• Route and audit owners map to guidance ids: adapters/delegated, shell/essential, browser/essential, workspace/essential, play/authoring, troubleshooting/essential, registry/essential.
• SKILL.md keeps Play in charge of each delegated step: Rote documents end with ## Next gates and gate branches, and inside a Play step those are informational. The agent returns a declared event to Play, never follows a Rote gate past command_policy, and reads the digest from data.result.digest.
• The installer drops --package, checks only for the rote skill, and requires rote 0.89.0 or newer.
• When rote is not installed, the setup handoff points the user at https://getrote.dev, because rote guidance setup/essential needs the binary.

Compatibility

• Breaking: Play now requires rote 0.89.0. Receipts with executor.kind: skill are rejected.
• Keep this PR in draft until rote 0.89.0 is released, then merge it the same day.

BREAKING CHANGE: Play requires rote 0.89.0 or newer and delegates to rote guidance ids instead of rote skills; handoff receipts use executor.kind: guidance with an id and digest.

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