fix: preserve case-sensitive URL parts

[roian6]

Description

• Preserve path, query-name, query-value, and fragment casing in normalize_url while still relying on yarl to canonicalize scheme/host casing.
• Update the normalization docstring so it no longer implies all URL casing is trivial.
• Add regressions showing default unique keys no longer collide for case-distinct paths or query components.

Issues

• Closes: normalize_url lowercases the entire URL, silently deduplicating case-distinct pages #2008

Testing

• uv run pytest tests/unit/_utils/test_requests.py -q
• uv run poe lint
• uv run poe type-check
• git diff --check

I also attempted uv run poe unit-tests. After installing Playwright browsers, the suite reached 2152 passed, 6 skipped but still failed in tests/unit/browsers/test_stagehand_browser_plugin.py because the local environment lacks the Stagehand SEA binary (stagehand-linux-arm64). That failure appears unrelated to this URL normalization change.

Checklist

• CI passed

[Pijukatel]

Could you please write it as a parametrized test with 1 assert and 3 sets of parameters and ids explaining a specific test case (path_key, query_value_key, query_name_key)

[roian6]

Thanks! Updated the regression to a parametrized test with one assert and the requested ids: path_key, query_value_key, and query_name_key.

I also rebased onto the current origin/master and re-ran:

• uv run pytest tests/unit/_utils/test_requests.py -q (20 passed)
• uv run poe lint
• uv run poe type-check
• git diff origin/master --check

The Semgrep PR check is passing on the updated head 7108d4ba45093e60a1166676ec84e65a1cc654cb as well.

[vdusek]

Hi @roian6, thanks for the PR. However, this issue is currently milestoned for v2 because the fix would introduce breaking changes to how requests are represented in storages.

Because of that, this needs to be handled carefully as part of a major version update, along with an appropriate upgrade guide. I'm going to close this for now.