feat(core): add event cast narrowing detector

[anidroid1184]

Summary of the change

Adds a static-analysis detector (event_data_cast) that flags narrowing integer casts inside env.events().publish() call payloads. When a wider integer (e.g. i128, i64) is cast to a narrower type (e.g. u32) or changes signedness (i64 as u64) inside event emission, indexers receive truncated data silently.

The detector scans function bodies, tracks parameter types through the visitor, and recurses into tuples, method calls, and binary expressions within event payloads to catch lossy casts.

Fixes / Closes

Closes #804

Motivation and context

Event data is consumed off-chain by indexers and monitoring tools. A narrowing cast at the point of emission permanently loses information with no compiler warning — indexers see a truncated value and have no way to recover the original. This detector surfaces those casts during static analysis so developers can emit the full-width value or explicitly document the truncation.

Dependencies

• None (self-contained rule + insta snapshot)

Type of change

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Unit tests — 6 tests in event_data_cast.rs covering:

• Narrowing cast detection (i128 as u32)
• Widening casts ignored (u32 as u64)
• Casts outside event context ignored
• Multiple casts in one event payload
• Signedness change detection (i64 as u64)
• No-cast event payloads pass clean

Golden snapshot — insta snapshot via detector_snapshots.rs with a dedicated fixture exercising 4 violations across 3 functions and 3 safe patterns.

Command:

cargo test -p sanctifier-core -- event_data_cast

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[Gbangbolaoluwagbemiga]

@anidroid1184 , ci pipeline fails, pull from upstream and resolve pipeline failures

[anidroid1184]

@Gbangbolaoluwagbemiga sure

[Gbangbolaoluwagbemiga]

Please pull from upstream @anidroid1184 and resolve conflicts, also ensure all ci passes

[anidroid1184]

@Gbangbolaoluwagbemiga sure
The next commit won't have errors with the workflows

[Gbangbolaoluwagbemiga]

But this still has conflict and the ci fails, please fix before i merge it @anidroid1184 ...Looking forward to the fix

[anidroid1184]

@Gbangbolaoluwagbemiga sorry for be late. I'm still working on the ci pipeline. But still on my local enviroment. Can I send the new PR tomorrow?

[Gbangbolaoluwagbemiga]

Yes please, looking forward to that @anidroid1184....well done

[Gbangbolaoluwagbemiga]

@anidroid1184, ci still fails on this

[anidroid1184]

@Gbangbolaoluwagbemiga I'm sorry, I'll review again today, before end to campaign