Add vue/no-negated-v-if-condition rule

[waynzh]

related #2769

Found that the check and fix logic for ternaries is quite different. So, I extract v-if condition into a separate rule.

I’ll submit a follow-up PR later to implement vue/no-negated-condition as an extension of the no-negated-condition.

Update: #2795

[changeset-bot]

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Latest commit: fa09bb8

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eslint-plugin-vue	Minor

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[Copilot]

Pull Request Overview

Introduces a new ESLint rule vue/no-negated-v-if-condition to prohibit negated conditions in v-if/v-else(-if) when there’s an else branch, with auto-suggestion to invert and swap blocks.

• Add rule implementation with detection and fix suggestions
• Add comprehensive tests covering valid/invalid scenarios
• Register rule in plugin and document it

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tests/lib/rules/no-negated-v-if-condition.js	New test suite covering valid/invalid cases
lib/rules/no-negated-v-if-condition.js	Rule logic, detection of negated conditions, fix suggestion generators
lib/index.js	Plugin registration for the new rule
docs/rules/no-negated-v-if-condition.md	Rule documentation with examples
docs/rules/index.md	Added rule entry to the rules index

Comments suppressed due to low confidence (1)

docs/rules/no-negated-v-if-condition.md:57

• [nitpick] In the Related Rules section, this rule currently links to itself. Consider updating it to reference the core ESLint rule no-negated-condition or another relevant rule instead of duplicating itself.

- [no-negated-v-if-condition](https://eslint.org/docs/rules/no-negated-v-if-condition) 

[FloEdelmann]

Really cool, thank you! I have just one minor code style nitpick, the rest looks good to me 🙂

[ota-meshi]

(Sorry for the late reply. I've been very busy lately 😓)
LGTM! Thank you!