Update autoharness_analyzer for current AutoHarnessSkipReason variants

[srivatsansamraj]

The analyzer keeps its own copy of AutoHarnessSkipReason and fails to deserialize metadata from current Kani, which changed GenericFn to GenericFn(String) (model-checking/kani#4679) and added RequiresBoundedArguments (model-checking/kani#4691).

• Bring the enum in line with kani_metadata, keeping the strum strings identical so table text matches kani autoharness --list.
• Normalize a bare "GenericFn" to {"GenericFn": ""} before from_value, since CI builds the pinned Kani, which still writes the old form.
• Report RequiresBoundedArguments in its own type-category table instead of folding it into the missing-implementation one; the two need different remediation.
• Note --bounded-arguments in the README.

Verified with three hand-built kani-metadata.json fixtures (old format, GenericFn with payload, RequiresBoundedArguments): before the change they behave as described in #679, after it all three pass. cargo test covers the same three cases inline. Not run against a full std sweep.

Resolves #679

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 and MIT licenses.

[srivatsansamraj]

@Tianshu-Huang @acearyanarun @CYJ904 @wodex1nhaoIeng

Opened #679 for this; this PR is the fix. Feel free to take a look and verify when you get a chance.

[acearyanarun]

Looks good to me

[feliperodri]

LGTM — verified against upstream. The updated AutoHarnessSkipReason matches kani_metadata::AutoHarnessSkipReason at Kani HEAD exactly: variant names, payload shapes (GenericFn(String), RequiresBoundedArguments(Vec<(String, String)>)), and every #[strum(serialize = ...)] string are identical, so table text stays aligned with kani autoharness --list.

The compatibility shim is correct and necessary: kani#4679 (2026-08-21) and kani#4691 (2026-08-23) both postdate the pinned Kani 152c6a8 (2026-07-18), so the pinned Kani still serializes GenericFn as a bare string and never emits RequiresBoundedArguments. Without normalize_skip_reasons, the bare "GenericFn" would fail to deserialize into the newtype variant GenericFn(String); rewriting it to {"GenericFn": ""} fixes that while leaving the map form and all other variants untouched. That the "Kani Autoharness Analyzer" CI job (built against the pin) is green confirms the round-trip.

Splitting RequiresBoundedArguments into its own breakdown table via the parameterized skipped_breakdown_table(category_header, args_of, …) is a clean refactor and correctly keeps its remediation (--bounded-arguments) distinct from MissingArbitraryImpl. The three inline fixtures cover old form / payload / bounded-arguments.

Minor, non-blocking: with the current pin the bounded-arguments table will always render empty (that reason is never produced yet) — fine as forward-compat, and it'll populate once the pin advances past rust-lang#4691.

Approving.