Update capstone-next and support Alpha instruction ID variants

[b1llow]

Your checklist for this pull request

• I've read the guidelines for contributing to this repository.
• I made sure to follow the project's coding style.
• I've documented every RZ_API function and struct this PR changes.
• I've added tests that prove my changes are effective (required for changes to RZ_API).
• I've updated the Rizin book with the relevant information (if needed).
• I've used AI tools to generate fully or partially these code changes and I'm sure the changes are not copyrighted by somebody else.

Detailed description

This PR updates the bundled capstone-next revision from
3df6ff015fb6afd81307e325fdd9c82dbf184b28 to
ae11e4232cb1f0df4847bf2d66825b9f1cb119a2.

The newer Capstone revision uses uppercase Alpha instruction identifiers such
as ALPHA_INS_*, while older revisions expose Alpha_INS_*. A Meson feature
probe now detects which variant is available, and the Alpha analysis plugin
uses the RZ_ALPHA_INS() compatibility macro to support both forms.

The affected test expectations are also updated:

• Use the source register emitted by the updated Alpha decoder.
• Remove invalid ColdFire fmovem encodings now rejected by Capstone.
• Expect the correct .l suffix for long ftrap instructions.

This PR does not change any RZ_API interfaces and does not require a Rizin
book update.

OpenAI Codex with the GPT-5 model was used to help implement, review, split,
and validate these changes. The resulting changes were manually reviewed and
tested.

[codecov]

Codecov Report

❌ Patch coverage is 37.50000% with 10 lines in your changes missing coverage. Please review.
✅ Project coverage is 50.00%. Comparing base (1c4bcf6) to head (2715a63).

Files with missing lines	Patch %	Lines
librz/arch/p/analysis/analysis_alpha_cs.c	50.00%	6 Missing ⚠️
librz/main/rz-asm.c	0.00%	4 Missing ⚠️

Additional details and impacted files

Files with missing lines	Coverage Δ
librz/main/rz-asm.c	52.72% <0.00%> (-0.38%)	⬇️
librz/arch/p/analysis/analysis_alpha_cs.c	56.83% <50.00%> (ø)

... and 12 files with indirect coverage changes

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