[BUG] Smoke-test receiver should accept dispatch tag payload

[c-vigo]

Description

Two issues in assets/smoke-test/.github/workflows/repository-dispatch.yml:

1. Payload key mismatch: Candidate release dispatch sends client_payload.tag, but the deployed smoke-test receiver workflow validates client_payload.rc_tag, causing dispatch-triggered runs to fail at validation.

2. Cross-repo reference: The deploy commit message uses Refs: #258, but this runs in the smoke-test repo context where issue [FEATURE] Automated RC deploy-and-test via PR in smoke-test repo #258 does not exist. It should use a fully-qualified reference (Refs: vig-os/devcontainer#258).

Steps to Reproduce

1. Trigger candidate release in vig-os/devcontainer.
2. Observe successful dispatch from release.yml.
3. Open triggered run in vig-os/devcontainer-smoke-test.
4. See validation failure in Validate dispatch payload.

Expected Behavior

Receiver accepts client_payload.tag and continues to deploy/CI jobs. Deploy commits reference the correct cross-repo issue.

Actual Behavior

Receiver run fails early in payload validation and downstream jobs are skipped. Deploy commits (when they succeed) link to a non-existent local issue.

Environment

• OS: GitHub Actions Ubuntu runner
• Container Runtime: N/A
• Image Version/Tag: 0.3.0-rc1
• Architecture: N/A

Additional Context

• Triggering release run: https://github.com/vig-os/devcontainer/actions/runs/23016037898
• Failed smoke-test run: https://github.com/vig-os/devcontainer-smoke-test/actions/runs/23016596595
• Failed job: https://github.com/vig-os/devcontainer-smoke-test/actions/runs/23016596595/job/66841363171
• Related incident: Release 0.3.0-rc1 failed -- automatic rollback #283
• Cross-repo reference flagged by Copilot: chore: deploy latest devcontainer to enable remote repository dispatch workflows devcontainer-smoke-test#25

Possible Solution

1. Update receiver to accept client_payload.tag (already correct in source-of-truth assets/smoke-test/.github/workflows/repository-dispatch.yml; needs manual re-deploy to smoke-test repo).
2. Change Refs: #258 to Refs: vig-os/devcontainer#258 in the deploy commit message template.

After the fix, the user must manually re-deploy the smoke-test workflow before triggering the release workflow again.

Changelog Category

Fixed

Acceptance Criteria

• Receiver workflow accepts client_payload.tag
• Deploy commit references correct cross-repo issue
• Validation step succeeds when dispatch contains tag
• Manual re-deploy is documented and completed before re-triggering
• TDD compliance (see .cursor/rules/tdd.mdc)

[c-vigo]

1. Payload key mismatch: Candidate release dispatch sends client_payload.tag, but the deployed smoke-test receiver workflow validates client_payload.rc_tag, causing dispatch-triggered runs to fail at validation.

Fixed in devcontainer-smoke-test/#24