* main: (248 commits)
  [ty] bump conformance suite commit (astral-sh#24848)
  [ty] Pass unmapped type variables to `SpecializationBuilder::build_with` (astral-sh#24809)
  [ty] Avoid bookkeeping for unannotated functions (astral-sh#24842)
  [ty] Optimize signature checking based on number of arguments (astral-sh#24674)
  [ty] Avoid eagerly inferring legacy generic context (astral-sh#24841)
  [ty] Skip decorator inference for undecorated functions (astral-sh#24839)
  [ty] solve unions against generic protocols (astral-sh#24837)
  [ty] Lazily allocate parameter type builders (astral-sh#24838)
  [ty] Lazily compute call argument fallbacks (astral-sh#24836)
  [ty] Avoid collecting type context callables (astral-sh#24835)
  Bump ecosystem-analyzer to e7576e6 (astral-sh#24834)
  [ty] Support basic narrowing with aliased conditional expressions (astral-sh#24302)
  [ty] Fix project and workspace selection (astral-sh#24824)
  [ty] Fix missing memory usage attributes (astral-sh#24823)
  Fix setting selection for multi folder workspace (astral-sh#24819)
  Improve diagnostics for implicit calls to a possibly unbound unary operator. (astral-sh#24816)
  [ty] Update review pool (astral-sh#24818)
  Bump 0.15.12 (astral-sh#24815)
  [ty] Complete support for more detailed diagnostics on possibly unbound errors from implicit dunder calls against unions. (astral-sh#24676)
  Implement `#ruff:file-ignore` file-level suppressions (astral-sh#23599)
  ...