refactor: feature activation handling

[glevco]

Motivation

In preparation for new features that will undergo the Feature Activation process, this PR performs a few refactors to simplify and unify code. Before, we were performing similar operations individually for each feature: count checkdatasig, nanos, and fee tokens. This will only grow as we add new features. Now, this handling is unified.

Acceptance Criteria

• Refactor Feature Activation utils, removing the is_nano_active and is_fee_active functions, and creating the new Features class, which unifies those functions in the Features.from_vertex method.
• Refactor the Feature enum so it's a StrEnum.
• Refactor VerificationParams to use the new Features dataclass instead of individual attributes per feature.
• No changes in behavior.

Checklist

• If you are requesting a merge into master, confirm this code is production-ready and can be included in future releases as soon as it gets merged

[github-actions]

Bencher Report

Branch	refactor/features
Testbed	ubuntu-22.04

Click to view all benchmark results

Benchmark	Latency	Benchmark Result minutes (m) (Result Δ%)	Lower Boundary minutes (m) (Limit %)	Upper Boundary minutes (m) (Limit %)
sync-v2 (up to 20000 blocks)	📈 view plot 🚷 view threshold	1.70 m (-1.22%) Baseline: 1.72 m	1.55 m (91.11%)	2.06 m (82.32%)

🐰 View full continuous benchmarking report in Bencher

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.34%. Comparing base (a010288) to head (c7dd8a7).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1568      +/-   ##
==========================================
+ Coverage   86.33%   86.34%   +0.01%     
==========================================
  Files         437      437              
  Lines       33645    33652       +7     
  Branches     5258     5261       +3     
==========================================
+ Hits        29047    29058      +11     
+ Misses       3594     3590       -4     
  Partials     1004     1004              

☔ 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.