fix(perf): pass symbolsOnly to parseFilesWasmInline for small-batch incremental builds

[carlos-alm]

Problem

parseFilesWasmForBackfill accepts an opts.symbolsOnly flag that is intended to skip AST/complexity/CFG/dataflow visitors for callers that only consume definitions/calls/typeMap (native post-passes). However, when filePaths.length <= INLINE_BACKFILL_THRESHOLD (16 files), the function falls back to parseFilesWasmInline, which ignores opts.symbolsOnly and always runs full extraction.

This means the symbolsOnly optimization introduced in PR #1436 is a no-op for typical 1-file incremental rebuilds (which are exactly the path the post-pass scoping fix targets).

Impact

• No correctness regression — this is a missed optimization only
• The benchmark gains from PR fix(perf): consolidate extractor walks and scope native post-passes (v3.12.0 publish gate) #1436 are real (they come from file scoping in the proto-methods post-pass), not from symbolsOnly
• The gap only materializes on repos where the changed JS/TS file count exceeds 16 files

Fix

Add an analysis parameter to parseFilesWasmInline and plumb EXTRACT_ONLY through when opts.symbolsOnly is true. This requires modifying the extractor entry points (extractSymbolsQuery/extractSymbolsWalk) to accept and respect an analysis-mode flag, skipping their AST/complexity/CFG/dataflow sub-walks.

Deferred from PR #1436 review (Greptile P2, Claude flagged as non-blocking).