feat(haskell): add tree-sitter-haskell language support

[alexbiehl]

Adds Haskell (.hs) as a first-class extracted language, following the existing LanguageConfig/_extract_generic pattern (modeled on Kotlin).

What's included

• tree-sitter-haskell>=0.23,<0.24 as a core dependency (abi3 wheels exist for all platforms).
• _HASKELL_CONFIG — maps data_type/newtype/type_synomym/class/instance → containers, function/bind → functions, import → imports, apply/variable/qualified → calls.
• _import_haskell — reads the import node's module field (Haskell-specific; Kotlin uses path).
• A Haskell branch in walk_calls — Haskell application nests (f x y → apply(apply(f, x), y)), so it descends the leftmost function field for the direct callee, and also treats bare variable/qualified leaves as calls so higher-order uses (the area in map area xs) attribute to the caller.
• extract_haskell, .hs in _DISPATCH, .hs in detect.CODE_EXTENSIONS.
• Fixture tests/fixtures/sample.hs + 7 tests (skipif when the grammar is absent).

Two grammar gotchas handled

1. In tree-sitter-haskell a function type (Shape -> Double) is also a function node (nested under signature). A naïve config emits a spurious Double() "function". Fixed by name_fallback_child_types=() so type-level nodes (which lack a name field) are skipped. Regression test included.
2. type_synomym is the grammar's real (misspelled) node-type string — kept verbatim, not "corrected".

Verification

• 7 Haskell tests pass; full test_languages.py = 257 passed, 13 skipped (optional tree-sitter-dm), no regressions.
• Exercised on a large real Haskell codebase (~470 .hs files): clean parse, with data types, classes, functions, imports, and cross-function call edges (e.g. updateS7TagMonitor → resolveUpdateDataType).

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