full-analysis: Parallelize signature analysis phase

[aviatesk]

Parallelize signature analysis using Threads.@spawn, leveraging the thread-safe inference pipeline introduced in Julia v1.12. Each analysis task creates its own analyzer with fresh local caches to avoid data races.

Key changes:

• Add SignatureAnalysisProgress struct with atomic fields for thread-safe progress tracking
• Make LS_ANALYZER_CACHE thread-safe using CASContainer
• Move AtomicContainers include earlier to make it available in Analyzer.jl

On a 4-core machine (--threads=4,2):

• CSV.jl first-time analysis: 30s -> 18s (~1.7x faster)
• JETLS.jl first-time analysis: 154s -> 36s (~4.3x faster)

Performance experiments

The measurement results below are for --threads=auto (--threads=4,2).

JETLS.jl

master 1dac93f vs. avi/parallelize-sig-analysis

JETLS Branch	First time analysis (generation=0)	Re-analysis (generation=1)	Re-analysis (generation=2)
master	153.58	18.64	20.43
avi/parallelize-sig-analysis	35.89	14.2	14.66

CSV.jl

04ec1cf

JETLS Branch	First time analysis (generation=0)	Re-analysis (generation=1)	Re-analysis (generation=2)
master	29.71	12.31	7.0
avi/parallelize-sig-analysis	18.45	5.68	4.1

[codecov]

Codecov Report

❌ Patch coverage is 75.00000% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 65.65%. Comparing base (1dac93f) to head (18b86dc).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
src/analysis/Interpreter.jl	72.41%	8 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #351      +/-   ##
==========================================
+ Coverage   65.55%   65.65%   +0.09%     
==========================================
  Files          41       41              
  Lines        4207     4219      +12     
==========================================
+ Hits         2758     2770      +12     
  Misses       1449     1449              

Flag	Coverage Δ
JETLS.jl	65.65% <75.00%> (+0.09%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.