chore(deps): co-bump llama-index-llms-openai + llama-index-llms-openai-like in /worker_plan

[neoneye]

Summary

Co-bumps two pinned packages in worker_plan/pyproject.toml:

• llama-index-llms-openai 0.6.12 → 0.7.8
• llama-index-llms-openai-like 0.5.3 → 0.7.2

Why

Dependabot opened these as two separate PRs (#679 and #688), and each failed CI on its own because the two packages have mutually-coupled version ranges:

• llama-index-llms-openai-like 0.7.2 requires llama-index-llms-openai>=0.7.0,<0.8
• llama-index-llms-openai-like 0.5.3 requires llama-index-llms-openai<0.7

So bumping either pin in isolation creates a resolution conflict. The 0.7.8 + 0.7.2 pair satisfies each other; this PR bumps both together. Once merged, dependabot will auto-close #679 and #688.

Test plan

• CI passes (resolution is now satisfiable)

[neoneye]

Closing — this co-bump cannot pass CI either. Investigation reveals the real blocker: llama-index-llms-openrouter (latest 0.5.0, released 2026-03-12) caps llama-index-llms-openai-like<0.7. Until upstream ships an openrouter release that supports openai-like 0.7.x, neither this PR nor #688 nor #679 can be merged. Closing #688 and #679 too with the same context.