fix: skip Kotlin operator convention imports in unused-import detection

[ariancovac]

Problem

Kotlin invokes convention (operator) functions implicitly by the compiler. The clearest case: import androidx.compose.runtime.getValue / setValue are required for Compose State/MutableState property delegation (val x by someState, var y by mutableStateOf(...)), yet the names never appear in the file text.

Textual unused-import detection cross-references the imported name against the file body, so it flagged these live imports as unused on every scan (in one real Compose project: 26 findings across 15 files). Removing them breaks compilation — the reviewer either "fixes" a false positive into a build break, or has to dismiss the same findings after every rescan.

Fix

• Add an optional implicit_import_names: frozenset[str] field to TreeSitterLangSpec: names a language invokes implicitly by convention, which a textual reference search cannot rule out.
• Populate it for KOTLIN_SPEC with the Kotlin convention-function table: property delegation (getValue, setValue, provideDelegate), unary/arithmetic/ranges, augmented assignments, containment/indexing/invocation/comparison (contains, get, set, invoke, compareTo, equals), iteration (iterator, next, hasNext), and infix bitwise (and, or, xor, shl, shr, ushr).
• detect_unused_imports skips imported names present in that set. This trades a small amount of recall (a genuinely unused operator-named import goes unreported) for eliminating a false-positive class that directly invites build-breaking fixes — consistent with the detector's conservative stance elsewhere (e.g. skipping errorful parses).
• Other languages are unaffected (the field defaults to empty).

Test

test_unused_imports_skip_implicit_convention_names: with an implicit_import_names-carrying spec, an unreferenced getValue import yields no findings; with a plain spec it is still flagged. Suite: 29 passed in test_treesitter_analysis_direct.py + test_phase_builders.py.

[awdemos]

Reviewed this against #676 — both fix the same Compose getValue/setValue unused-import false positive, but with different designs, and #676 is the stronger implementation:

• fix: skip Kotlin operator convention imports in unused-import detection #740 adds TreeSitterLangSpec.implicit_import_names and blanket-skips ~40 operator names unconditionally. A/B on real Kotlin files: a genuinely dead import …getValue with no by in the file is silenced, and dead imports named get, equals, and, or, contains, iterator can never be reported again. It also can't cover componentN destructuring (a frozenset can't express component\d+), so that false positive remains. The test suite is all FakeNode mocks.
• fix: don't flag Kotlin delegation/destructuring imports as unused #676 adds implicit_import_uses — (name_pattern, body_pattern) pairs — so an import is only forgiven when the triggering syntax is actually present (by delegation, val (a, b) destructuring). Same false positive fixed; dead imports still found; covers componentN; end-to-end tests with the real tree-sitter grammar.

If there are operator names in #740's list you want coverage for, the right move is folding them into #676's mechanism (conditional on syntax) rather than landing the unconditional skip. Suggest closing this in favor of #676.