[DeusData]

The #961/#1989 rescue re-adopts definitions from the preprocessed second
pass when they sit in a raw parse error, and drops a copy only when its QN
equals a raw one. When the two parses scope the same definition
differently, both copies survived:

• Linux lib/tests/randstruct_kunit.c: a macro-generated struct body makes
  the raw parse nest every later struct inside one ERROR region; the flat
  expanded copies were adopted next to the mis-nested raw ones (5
  duplicate groups).
• coreclr/rapidjson: the expanded parse nests utilcode.h classes wrongly
  or loses rapidjson's scopes, and both copies survived.

One rule at one decision point: an expanded and a raw definition with the
same label, name and start line but different QNs are one definition. The
raw copy wins and whatever the expanded pass attributed to the expanded QN
moves to it -- unless

• the raw copy's nesting exists only because of a raw ERROR region that
  the expanded parse resolved (the randstruct shape, six conditions in
  cbm_misnested_raw_twin): then the flat expanded copy replaces the raw
  one and the raw children (Fields, nested defs, call/usage scopes) are
  re-parented to it; or
• the raw copy's QN is already held by a raw definition of another label
  (coreclr inc/holder.h: the raw parse reads a FORCEINLINE constructor as
  a Function of the class's scope-less QN): then the expanded copy keeps
  its own, correct QN instead of vanishing into the Function's node.

Proof (macOS arm64):

• randstruct_kunit.c: 5 -> 0 duplicate groups, 12 Fields re-parented to
  the flat structs, CALLS/USAGE/WRITES unchanged.
• dotnet/runtime native subset (src/coreclr + src/native): 700 -> 183
  groups; the remaining groups are no raw/expanded pairs at one site.
• redis: node and edge sets byte-identical.
• New tests (RED without the change): extraction
  extract_c_misnested_raw_struct_replaced_by_flat_copy,
  extract_cpp_preprocessed_rescue_skips_raw_def_on_same_line,
  extract_cpp_rescue_keeps_expanded_class_when_raw_qn_is_taken (fixture
  delta-minimized from holder.h).
• conditional_variants, extraction, c_lsp, pipeline, edge_types_probe,
  parse_coverage, lsp_resolution_probe: 1854 passed.