fix(eve): defer context during approval resume

[iroiro147]

Summary

• defer channel context attached to pending tool-approval responses until the next internal step
• keep the approval-response tool message as the tail of the approval-resume model call so approval collection can run
• add resolver and harness regressions for context-bearing approval resumes

Refs #529.
Related #460.

Tests

• pnpm guard:invariants
• pnpm --filter eve exec vitest run --config vitest.unit.config.ts src/harness/input-requests.test.ts src/harness/tool-loop.test.ts (171 passed)
• pnpm --filter eve typecheck
• pnpm --filter eve exec oxlint src/harness/input-requests.ts src/harness/input-requests.test.ts src/harness/tool-loop.ts src/harness/tool-loop.test.ts --deny-warnings
• pnpm exec oxfmt --check packages/eve/src/harness/input-requests.ts packages/eve/src/harness/input-requests.test.ts packages/eve/src/harness/tool-loop.ts packages/eve/src/harness/tool-loop.test.ts .changeset/linear-approval-context-resume.md
• pnpm changeset status --since origin/main
• git diff --check

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