Extract shared MCP router core

[rudijetson]

Contract

• Extracts a transport- and execution-independent router dispatcher into @learnrudi/mcp.
• Preserves local stdio behavior, canonical and portable tool names, cache/inline/live precedence, disabled-stack behavior, downstream error propagation, and JSON-RPC lifecycle behavior.
• Keeps local filesystem, environment, secrets, subprocess, and pool ownership in the CLI adapter.
• Adds a package-specific, manual, main-only npm trusted-publishing workflow for @learnrudi/mcp@1.1.0.
• Separates no-OIDC verification from the minimal OIDC publish job; the privileged job uses a fresh same-SHA credential-free checkout, executes no repository or dependency code, repacks with lifecycle scripts disabled, and pins the npm registry at command-line precedence.
• Adds no hosted listener, OAuth behavior, relay, stack behavior change, workflow dispatch, or package publication.

Immutable CLI revision: 306db12824319e6c4b8045c2d90798f2e3960d6b.

Proof

• Release workflow contract: 7/7 passed.
• Node 24.20.0 @learnrudi/mcp package inventory and exact package command: 29/29 passed.
• Full CLI suite: 787/787 passed.
• Node 20 build passed; generated outputs and package metadata remained unchanged after a frozen install.
• Production audit: zero known vulnerabilities.
• MCP dry-run pack: exact nine-file allowlist; root dry-run pack: intended six files.
• Workflow YAML parsed and all 12 shell blocks passed bash -n; immutable action pins matched their upstream tags.
• GitHub Quality run 33585695530 passed on the exact corrective head.
• Edited-file SWE debt scan: zero findings; git diff --check: passed.
• Final independent Standards/Spec/Proof review: PASS with no P0-P3 findings; both prior P1 findings are closed.
• Admin-Mac exact-ref ancestry and feature-diff audit: passed without changing its canonical checkout.

Residual gates

• npm currently exposes only @learnrudi/mcp@1.0.0; 1.1.0 remains unpublished.
• Merge, exact npm trusted-publisher configuration, manual OIDC workflow dispatch, publication, and registry provenance/immutability verification remain separately authorized gates.
• Hosted dependency integration, provider setup, migration, deployment, DNS, and live smoke/rollback are not authorized by this draft PR.

Companion drafts: learnrudi/registry#62, learnrudi/cloud#19, and learnrudi/rudi-system#26.