test: Deflake adaptive crawler routing tests against request retries

[vdusek]

test_adaptive_crawling[Enforced rendering type detection] fails intermittently on Windows CI with
assert 4 == 2 (example run).
When the Playwright sub-crawl stalls and times out, BasicCrawler retries the whole request - which is correct
behavior - but the test counts every hook and handler invocation and pulls each rendering type from a shared
cycle(). The retry therefore fires the pre-navigation hook a second time for the same URL and advances the cycle,
so the expected 2 becomes 4.

The fix makes the assertions insensitive to retries instead of tolerating them:

• test_adaptive_crawling and test_adaptive_crawling_parsel assert the set of URLs routed to each sub crawler
  rather than raw invocation counters.
• _SimpleRenderingTypePredictor memoizes its prediction per URL, so a retried request keeps the rendering type it
  was first assigned.

Verified with deterministic fault injection - patching PlaywrightCrawler._navigate to fail the first navigation
per URL, which runs after the pre-navigation hooks and so reproduces the CI sequence exactly. Before the change 4
of the 5 affected cases fail, including the exact assert 4 == 2; after it all pass, plus 0/100 failures under a
repeated parallel run.

No production code is touched, and the routing property under test is unchanged: wrong routing, a missing
pre-navigation hook, or a URL reaching both sub crawlers all still fail.

✍️ Drafted by Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.72%. Comparing base (6deabad) to head (d3d4524).
⚠️ Report is 10 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2198      +/-   ##
==========================================
+ Coverage   93.61%   93.72%   +0.10%     
==========================================
  Files         181      181              
  Lines       12825    12825              
==========================================
+ Hits        12006    12020      +14     
+ Misses        819      805      -14     

Flag	Coverage Δ
unit	93.72% <ø> (+0.10%)	⬆️

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