Run the complete policy suite from the README and CI

Parent Quest: #254

Story

As an effectionx contributor, I want to run the complete policy suite from the README before opening a pull request, so I see the same policy verdicts and evidence that CI will evaluate.

The README is the executable entrypoint:

xmd run README.md#Policies

Current gap

Policies are discoverable through .policies/index.md, but the README does not compose them into a runnable workflow. Local review and CI therefore have no shared entrypoint, and a new policy could be documented without becoming part of the enforced suite.

Contract

Add a Policies XMD entrypoint to the README that discovers every active policy from the authoritative policy index and executes each policy’s public Validate entrypoint.

The workflow:

• uses the same command, policy inventory, validator declarations, tool versions, and repository inputs locally and in CI;
• runs lint-backed policies through their declared @effectionx/lint rules;
• runs AI-backed policies through their declared review procedures;
• reports each policy, validation method, verdict, and supporting evidence;
• exits unsuccessfully when any active policy fails or cannot run;
• never silently skips a policy because a validator, credential, input, or entrypoint is unavailable; and
• does not maintain a second hard-coded policy list in the README or CI configuration.

The README explains prerequisites and shows both the complete-suite command and the individual-policy command used for focused investigation.

Acceptance

• A contributor can start from a clean checkout, follow the README, and run the complete active policy suite.
• CI invokes the same README #Policies entrypoint.
• The aggregate result identifies every active policy and how it was validated.
• Adding an active policy without a runnable Validate entrypoint makes the aggregate workflow fail.
• A deliberate lint-backed violation produces a non-zero result naming the policy and rule.
• A deliberate AI-backed violation produces a non-zero result naming the policy and required evidence.
• An unavailable validator prerequisite fails with an actionable diagnostic rather than being reported as a pass.
• The historical corpus from #258 passes before the aggregate workflow is accepted.
• Existing contributor commands for build, typecheck, lint, format, and tests remain documented and available.

Evidence

Verification records the output of the README entrypoint locally and in CI, including one lint-backed failure, one AI-backed failure, one unavailable-validator failure, and a clean full-suite pass.

Dependencies

• Depends on #257 for independently executable policies.
• Depends on #258 for historical fail/pass verification.
• Completes the contributor-facing outcome of #254.

Out of scope

• Policies outside the effectionx repository
• Deno lint compatibility
• A separate CI-only policy implementation
• Silently downgrading failed or unavailable validators

Start with the README #Policies entrypoint and .policies/index.md, then inspect how independently executable policies and their public Validate entrypoints are defined under dependencies #257 and #258. Run xmd run README.md#Policies from a clean checkout and compare it with CI; done means every active policy is reported, failures or unavailable validators are non-zero, and existing contributor commands remain documented.