fix(ts-query): correct predicate and directive completions

[vitallium]

Summary

Follow up on #347 to align query completions and argument validation with ts_query_ls and Zed's query runtime.

• Let ts_query_ls generate not-eq and not-match from their base predicates, and disable automatic not- expansion for the explicit quantified variants. This avoids unsupported suggestions such as #not-not-eq? and #not-any-eq?, while preserving the supported #not-any-of? spelling.
• Accept either a capture or a string as the second equality operand, including for negated and quantified variants.
• Remove is/is-not and downcase!/select-adjacent!/strip! completion entries because Zed does not execute those operations. Keep set!, which Zed consumes through property settings.

The capture additions from #347 and all existing query files are unchanged. In particular, cleanup of the existing no-op downcase! use is outside this PR.

Validation

• cargo test --locked: 82 tests passed.
• JSON Schema validation against the configuration's declared schema passed.
• Three temporary Rust checks using the actual ts_query_ls configuration deserializer at 305587adaf39719152866012edd700c53036c7a6: all failed against the original configuration, then passed after the fix. They verify the expanded predicate names, equality argument types, and directive names. The temporary harness is not added as a project dependency or committed test.
• git diff --check passed.

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