[NFC] `const` BPA for VisibilityEstimator

PiperOrigin-RevId: 953113888

Clean up includes in xls/dslx/lsp.

PiperOrigin-RevId: 952358702

[Explicit State Access] Guard state_read references in schedule_graph…

… and clone_nodes_into_block

PiperOrigin-RevId: 951672414

Refactor builder channel and state element API to store errors on the…

… builder.

Currently, various builder methods like `AddInputChannel`, `AddOutputChannel`, `AddChannel`, and `UnreadStateElement` return `StatusOr<...>` values which require checking using `XLS_ASSIGN_OR_RETURN` or `XLS_ASSERT_OK_AND_ASSIGN`.

This change refactors these methods to return wrapper types `BReceiveChannel`, `BSendChannel`, `BChannel`, `BChannelWithInterfaces`, and `BStateElement` and to store any validation failures or errors inside the builder itself (analogous to how `BValue` works). This makes the builder API cleaner and more ergonomic.

All tests and translation logic have been updated to match the new API.

PiperOrigin-RevId: 951103808

[opt] Rollback fix CanonicalizePass clamping until missing IsBits che…

…cks are readded

PiperOrigin-RevId: 949773835

[Explicit State Access] Support Decoupled Next in proc_state_narrowin…

…g_pass

PiperOrigin-RevId: 949131933

[ir] Optimize bits_ops::LongestCommonPrefixMSB with word-based operat…

…ions

This is used heavily by interval_ops::ExtractTernaryVector, which is essential to our `PartialInformation` implementation when transferring information from range to ternary.

PiperOrigin-RevId: 948063809

[codegen] Explicitly narrow over-width array indices

We already do this in most cases as part of our clamping logic. However, if we've proven the actual value is in-bounds, we previously didn't remember to make this narrowing explicit, which makes some Verilog linters complain.

PiperOrigin-RevId: 947297793

Update llvm versions in bazel lock file.

PiperOrigin-RevId: 945304704

[ir] Rewrite `IntervalSet::Normalize` for efficiency.

The normalization process now expands improper intervals and merges overlapping/abutting intervals in-place within the `intervals_` vector, reducing memory allocations and copies. We also take advantage of known information to simplify the overlapping/abutting checks.

PiperOrigin-RevId: 944765711