build(deps): bump GNSSSignals compat to 3.2

[giove-a]

Summary

Bump the GNSSSignals compat entry from "2.6" to "3.2", adopting the latest GNSSSignals release line.

-GNSSSignals = "2.6"
+GNSSSignals = "3.2"

Why no code changes were needed

The 2.x → 3.x changes in GNSSSignals were internal (code-LUT storage). GNSSDecoder only touches the stable public surface — signal types as dispatch tags (GNSSDecoderState(::GPSL5I, prn), etc.) plus gen_code/get_code_frequency in tests — so the bump is source-compatible.

The rest of the ecosystem is already on v3: Tracking ≥ 2.1 and Acquisition ≥ 2.6 both require GNSSSignals = "3".

Verification

Built against GNSSSignals 3.2.0 (master) — precompiles cleanly and the full suite passes:

Test Summary:  | Pass  Total     Time
GNSSDecoder.jl | 2459   2459  3m11.5s

Note

"3.2" was chosen deliberately: the new AbstractGPSSignal/AbstractGalileoSignal supertypes and the time-system API are new in 3.2.0. At time of writing 3.2.0 is on GNSSSignals master but not yet registered (registry tops out at 3.1.0), so CI resolution here will go green once 3.2.0 is registered.

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.15%. Comparing base (961e52a) to head (6cd74d1).

Additional details and impacted files

@@           Coverage Diff           @@
##           master      #70   +/-   ##
=======================================
  Coverage   98.15%   98.15%           
=======================================
  Files          14       14           
  Lines        1517     1517           
=======================================
  Hits         1489     1489           
  Misses         28       28           

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