fix(eve): add session cancellation by token

[iroiro147]

Summary

• add a runtime cancelSession path that cancels the workflow run owning a continuation token
• expose an authenticated DELETE /eve/v1/session route on the default eve channel for operator recovery
• document the cancellation contract and add the patch changeset for the published package

Refs #541.

Tests

• pnpm --filter eve exec vitest run --config vitest.unit.config.ts src/execution/workflow-runtime.test.ts src/public/channels/eve.test.ts src/internal/nitro/routes/channel-dispatch.test.ts src/channel/send.test.ts src/channel/cross-channel-receive.test.ts src/channel/schedule.test.ts src/public/channels/chat-sdk/chatSdkChannel.test.ts src/public/channels/github/githubChannel.test.ts src/public/channels/linear/linearChannel.test.ts src/public/channels/teams/teamsChannel.test.ts src/runtime/session-callback-route.test.ts test/eve-run-stream-channel.test.ts
• pnpm --filter eve exec vitest run --config vitest.scenario.config.ts test/scenarios/cross-channel-receive.scenario.test.ts test/scenarios/schedule-trigger.scenario.test.ts
• pnpm --filter eve run typecheck
• pnpm docs:check
• pnpm guard:invariants
• pnpm exec oxlint --deny-warnings
• pnpm exec oxfmt --check ...
• git diff --check

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