Linter: Allow render target names as shorthand locals

[Parthu-M]

Summary

• stop treating template as a shadowed partial option in shorthand render calls
• keep reporting options such as layout and collection, whose meaning silently changes between render forms
• add regression coverage for all seven mutually exclusive render targets (template, file, inline, body, plain, html, and renderable)

Why

Render-target options are mutually exclusive with partial:. Using one while switching to the keyword partial form creates a contradictory call instead of silently changing a local into a valid render option, so reporting only template was inconsistent and noisy.

Fixes #2137

Validation

• focused rule harness: target names produced 0 offenses; layout still produced 1 offense
• oxlint on the changed rule and regression test
• git diff --check

The full linter suite is left to CI because this Windows checkout cannot generate the Ruby/Bundler-backed core artifacts required by the current workspace packages.

AI assistance

Codex helped identify the issue, implement the focused patch, and run validation. I reviewed the final diff before submission.