Support univariate Laurent divisibility over non-domains

[cxzhong]

This implements the univariate phase of #41318. It is a narrower alternative
to #41327: multivariate Laurent polynomial rings over non-integral domains keep
their existing guard.

For a coefficient ring A, the implementation uses the standard isomorphism
between A[x, x^-1] and A[x, y]/(xy - 1). Before embedding an element in the cover, it
removes its overall Laurent monomial factor, which is a unit. This keeps
Groebner-basis work independent of a harmless global exponent shift.

The change:

• preserves the existing integral-domain divisibility and ideal-membership
  paths;
• supports univariate divides and ideal membership over supported
  non-integral domains through the polynomial cover;
• reuses the ring's existing cover and lazily caches each Laurent ideal's
  extended ideal;
• handles zero, identical, and monomial-unit cases without Groebner-basis
  work;
• raises NotImplementedError for unsupported polynomial backends instead of
  silently returning a false negative.

Performance

Measured against the compiled develop baseline on one pinned CPU,
alternating variants across four fresh processes (nine inner rounds each):

Scenario	develop	This PR	Change
integral-domain divides, false	5.644 us	5.677 us	+0.6%
integral-domain divides, true	5.518 us	5.482 us	-0.7%
integral-domain ideal, cold	15.793 us	15.857 us	+0.4%
integral-domain ideal, hot	9.053 us	8.990 us	-0.7%
Zmod(8) cover divisibility	unsupported	263.7 us	new
same case shifted by 10^12	unsupported	256.3 us	shift-independent
monomial unit shifted by 10^12	unsupported	5.25 us	fast path
Zmod(8) ideal, cold / hot	unsupported	292.4 / 19.77 us	14.8x cache benefit

Tests

• ./sage -t --warn-long 5.0 src/sage/rings/polynomial/laurent_polynomial.pyx src/sage/rings/polynomial/laurent_polynomial_ideal.py src/sage/rings/polynomial/laurent_polynomial_ring_base.py
  -- 767 tests passed.
• Randomized comparison of normalized and signed cover lifts over Zmod(4),
  Zmod(6), Zmod(8), and Zmod(12): 180 membership cases and 180 known
  multiples passed.
• git diff --check passed.

Fixes #41318.

📝 Checklist

• The title is concise and informative.
• The description explains in detail what this PR is about.
• I have linked a relevant issue or discussion.
• I have created tests covering the changes.
• I have updated the documentation and checked the documentation preview.

⌛ Dependencies

None.

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