dev: Fuel const expr operator cost (#14215)

* Charge const-expr operators the configured fuel cost

Operators inside constant expressions - global initializers, element and
data segment offsets, element segment expressions - were each charged a
hardcoded 1 fuel unit, so `Config::operator_cost` had no effect on any
instantiation-time work.

Constant expressions are stored as `ConstOp` rather than
`wasmparser::Operator`, so add a `const_op_cost` lookup alongside the
existing `cost` lookup and use it in `translate_const_expr`. Default costs
are unchanged: every `ConstOp` still costs 1 with the default table.

* Charge the configured Call cost for the synthesized start call

`module_start` synthesizes the call to a module's `(start ...)` function
and manually replicates the fuel accounting that `fuel_before_op` performs
for `Operator::Call`. That replica used a hardcoded 1 rather than the
configured cost, so the `Call` entry of `Config::operator_cost` did not
apply to the start call. Look the cost up from the table instead.

* Note the const-expr fuel change in RELEASES.md and tighten the tests

`Config::operator_cost` shipped in 48.0.0, so applying it to const-expr
operators and the synthesized start call changes the observable behavior
of released public API; note it under 49.0.0's `Changed` section.

Also pin a second cost-table entry in the const-expr test so a mis-wired
`ConstOp` match arm cannot pass, and document where the two flat
per-function entry charges in the start-call test come from.

* Reuse the operator cost lookup for const-expr operators

Translate a `ConstOp` back into the `wasmparser::Operator` it was parsed
from and charge it through the existing `OperatorCostStrategy::cost`,
rather than carrying a second lookup over the same table. That removes
the duplicate cost mapping and the default table that had to be kept in
sync with `default_operator_cost` by hand.

Only `ConstOp::RefNull` cannot reproduce its immediate, since
`TypeConvert::convert_heap_type` has no reverse; a placeholder heap type
stands in, which is fine because the cost lookup ignores immediates.

Also drop the test doc comments and assert the start-call test under the
default cost table as well as a custom one.

* Move the const-expr operator translation onto `ConstOp`

`ConstOp::to_operator` now lives next to `ConstOp::from_wasmparser`, and
`translate_const_expr` charges through `OperatorCostStrategy::cost`
directly, so `tunables.rs` no longer carries any const-expr specific
lookup.

Run both new tests under `#[wasmtime_test]` like the neighbouring cost
tests, with `extended_const` enabled for the `i32.add` initializer, and
link the release note to the PR.

v48.0.1: Release Wasmtime 48.0.1 (#14197)

48.0.1

Released 2026-08-24.

Fixed

• Context slots in component compositions are now correctly managed.
  #14139

• The Host header is now set by default for HTTP requests sent with WASIp2.
  #14167

v48.0.0: Release Wasmtime 48.0.0 (#14169)

48.0.0

Released 2026-08-20.

Added

• Wasmtime has an initial implementation of the component model
  fixed-length-lists feature.
  #12315

• Wasmtime's reflection of component imports/exports now exposes external-id
  information.
  #13874

• Cranelift's alias analysis pass now eliminates dead stores.
  #13806
  #13947

• Winch now supports the wasm SIMD proposal on AArch64.
  #13911
  #13921
  #13928
  #13937
  #13945
  #13938
  #13946
  ...

• Cranelift now supports an AVX512-VNNI lowering for the dot-product wasm
  instruction and usdot on AArch64.
  #14006
  #14054

• Wasmtime's bindgen! macro now has an include_component_type option to
  generate a COMPONENT_TYPE constant with the encoded type of the world being
  bound.
  #14013

• Wasmtime now supports configurable fuel costs for variable-length wasm
  opcodes.
  #13931

Changed

• Host-implemented traits in wasmtime-wasi-http are now the same across
  wasip2/wasip3 and no longer require separate implementations/structures.
  #13810
  #13812
  #13835

• Wasmtime will now use the process_madvise syscall on Linux where available
  which can improve the performance of the pooling allocator when the
  deallocation batch size is configured to larger than 1.
  #13830

• Synchronous cancellation of streams/futures/subtasks now traps if the waitable
  was already in a waitable set.
  #13708

• Winch is now flagged to be compatible with component-model-async.
  #13845

• Wasmtime's pooling allocator now uses more sharding to reduce lock contention.
  #13840

• Wasmtime now requires Rust 1.95.0 to build.
  #13853

• Cranelift now has a uniform maximum size across all backends on the bounds of
  a function's stack frame.
  #13783

• Wasmtime's LinkerInstance for components now supports being reopened to
  gradually add more items.
  #13908

• The wasmtime-wasi crate's default configuration now denies creation of
  TCP/UDP sockets by default.
  #13936

• Wasmtime now configures async task context fields on realloc calls to zero.
  #13949

• Work has continued on continuous verification of Cranelift's lowering rules
  on AArch64.
  #13935
  #13929
  #13998

• Codegen for loads on AArch64 has been optimized slightly to improve sharing
  common sub-expressions.
  #13766

• Work continues on implementing the stack-switching proposal.
  #11717
  #13996
  #14052

• Permissions for wasi-filesystem in the implementation of the wasmtime-wasi
  crate have been simplified to either read-write or read-only for a directory.
  #14010

Fixed

• A late-drop of host-defined stream producers/consumers has been fixed.
  #13891

• Call hooks are now invoked around async yields when dealing with concurrent
  execution.
  #13871

• Extreme filesystem timestamps no longer cause panics.
  #13894

• An erroneous trap was fixed where an async-delivered write-closed event was
  sent to a future.
  #13914

• An erroneous trap where Wasmtime internally used the wrong thread id has been
  fixed.
  #13926

• Cross-component instance streams are no longer erroneously flagged as being
  intra-instance.
  #14018

• A panic in the wasmtime CLI with non-utf8 environment variables has been
  fixed.
  #14017

• Atomic waits on big-endian hosts have been fixed.
  #14027

• Enabling MPK with CoW images has been fixed.
  #14076

v47.0.4: Add release notes (#14183)

47.0.4

Released 2026-08-20

Fixed

• Guest controlled-size host heap allocation through WASIp3 streams.
  GHSA-x84v-gj2h-g759

• Filesystem sandbox escape when paths or symlinks contain trailing slashes.
  GHSA-vqjp-4c8c-hfgg

v46.0.3: Release Wasmtime 46.0.3 (#14170)

46.0.3

Released 2026-08-20

Fixed

• Guest controlled-size host heap allocation through WASIp3 streams.
  GHSA-x84v-gj2h-g759

• Filesystem sandbox escape when paths or symlinks contain trailing slashes.
  GHSA-vqjp-4c8c-hfgg

v36.0.14: Release Wasmtime 36.0.14 (#14172)

36.0.14

Released 2026-08-20

Fixed

• Filesystem sandbox escape when paths or symlinks contain trailing slashes.
  GHSA-vqjp-4c8c-hfgg

v24.0.13: Release Wasmtime 24.0.13 (#14173)

24.0.13

Released 2026-08-20

Fixed

• Filesystem sandbox escape when paths or symlinks contain trailing slashes.
  GHSA-vqjp-4c8c-hfgg

v47.0.3: Release Wasmtime 47.0.3 (#14037)

47.0.3

Released 2026-07-31.

Fixed

• Stores can mix up type indices between engines.
  GHSA-hgjw-h833-99q9

• Preemption and traps during bulk operations enable breaking internal VM state.
  GHSA-2hw9-mc66-jc2q

v46.0.2: Release Wasmtime 46.0.2 (#14038)

46.0.2

Released 2026-07-31.

Fixed

• Stores can mix up type indices between engines.
  GHSA-hgjw-h833-99q9

• Preemption and traps during bulk operations enable breaking internal VM state.
  GHSA-2hw9-mc66-jc2q

v36.0.13: Release Wasmtime 36.0.13 (#14035)

36.0.13

Released 2026-07-31.

Fixed

• Stores can mix up type indices between engines.
  GHSA-hgjw-h833-99q9