feat: Add PersistentHugr

[lmondada]

The base of this PR will be moved to main once #2070 has been merged in.

Status: The API and main structs have been defined. Most of the core logic has yet to be implemented.

Status: PR is ready. The trait implementations for HugrView, VerifyPatch and ApplyPatch will be in a separate PR once progress on those is unblocked.

Closes #2096

[hugrbot]

This PR contains breaking changes to the public Rust API.
Please deprecate the old API instead (if possible), or mark the PR with a ! to indicate a breaking change.

cargo-semver-checks summary

--- failure enum_missing: pub enum removed or renamed ---

Description:
A publicly-visible enum cannot be imported by its prior path. A `pub use` may have been removed, or the enum itself may have been renamed or removed entirely.
      ref: https://doc.rust-lang.org/cargo/reference/semver.html#item-remove
     impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.40.0/src/lints/enum_missing.ron

Failed in:
enum hugr_core::hugr::rewrite::consts::RemoveError, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/consts.rs:18
enum hugr_core::hugr::rewrite::outline_cfg::OutlineCfgError, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/outline_cfg.rs:221
enum hugr_core::hugr::rewrite::replace::WhichHugr, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/replace.rs:433
enum hugr_core::hugr::rewrite::BoundaryPort, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/port_types.rs:14
enum hugr_core::hugr::rewrite::inline_call::InlineCallError, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/inline_call.rs:17
enum hugr_core::hugr::rewrite::replace::NewEdgeKind, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/replace.rs:31
enum hugr_core::hugr::rewrite::replace::ReplaceError, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/replace.rs:397
enum hugr_core::hugr::rewrite::simple_replace::SimpleReplacementError, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/simple_replace.rs:351
enum hugr_core::hugr::rewrite::SimpleReplacementError, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/simple_replace.rs:351
enum hugr_core::hugr::rewrite::insert_identity::IdentityInsertionError, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/insert_identity.rs:38
enum hugr_core::hugr::rewrite::inline_dfg::InlineDFGError, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/inline_dfg.rs:15

--- failure inherent_method_missing: pub method removed or renamed ---

Description:
A publicly-visible method or associated fn is no longer available under its prior name. It may have been renamed or removed entirely.
      ref: https://doc.rust-lang.org/cargo/reference/semver.html#item-remove
     impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.40.0/src/lints/inherent_method_missing.ron

Failed in:
ExtensionOp::cast, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/ops/custom.rs:131
ExtensionOp::extension_id, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/ops/custom.rs:136
ExtensionOp::cast, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/ops/custom.rs:131
ExtensionOp::extension_id, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/ops/custom.rs:136

--- failure module_missing: pub module removed or renamed ---

Description:
A publicly-visible module cannot be imported by its prior path. A `pub use` may have been removed, or the module may have been renamed, removed, or made non-public.
      ref: https://doc.rust-lang.org/cargo/reference/semver.html#item-remove
     impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.40.0/src/lints/module_missing.ron

Failed in:
mod hugr_core::hugr::rewrite::insert_identity, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/insert_identity.rs:1
mod hugr_core::hugr::rewrite, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite.rs:1
mod hugr_core::hugr::rewrite::replace, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/replace.rs:1
mod hugr_core::hugr::rewrite::inline_dfg, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/inline_dfg.rs:1
mod hugr_core::hugr::rewrite::outline_cfg, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/outline_cfg.rs:1
mod hugr_core::hugr::rewrite::consts, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/consts.rs:1
mod hugr_core::hugr::rewrite::inline_call, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/inline_call.rs:1
mod hugr_core::hugr::rewrite::simple_replace, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/simple_replace.rs:1

--- failure struct_missing: pub struct removed or renamed ---

Description:
A publicly-visible struct cannot be imported by its prior path. A `pub use` may have been removed, or the struct itself may have been renamed or removed entirely.
      ref: https://doc.rust-lang.org/cargo/reference/semver.html#item-remove
     impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.40.0/src/lints/struct_missing.ron

Failed in:
struct hugr_core::hugr::rewrite::outline_cfg::OutlineCfg, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/outline_cfg.rs:23
struct hugr_core::hugr::rewrite::replace::NewEdgeSpec, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/replace.rs:18
struct hugr_core::hugr::rewrite::inline_call::InlineCall, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/inline_call.rs:12
struct hugr_core::hugr::rewrite::replace::Replacement, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/replace.rs:57
struct hugr_core::hugr::rewrite::inline_dfg::InlineDFG, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/inline_dfg.rs:10
struct hugr_core::hugr::rewrite::insert_identity::IdentityInsertion, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/insert_identity.rs:18
struct hugr_core::hugr::rewrite::consts::RemoveConst, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/consts.rs:73
struct hugr_core::hugr::rewrite::simple_replace::SimpleReplacement, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/simple_replace.rs:26
struct hugr_core::hugr::rewrite::SimpleReplacement, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/simple_replace.rs:26
struct hugr_core::hugr::rewrite::Transactional, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite.rs:53
struct hugr_core::hugr::rewrite::consts::RemoveLoadConstant, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/consts.rs:13
struct hugr_core::hugr::rewrite::HostPort, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/port_types.rs:23
struct hugr_core::hugr::rewrite::ReplacementPort, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite/port_types.rs:27

--- failure trait_missing: pub trait removed or renamed ---

Description:
A publicly-visible trait cannot be imported by its prior path. A `pub use` may have been removed, or the trait itself may have been renamed or removed entirely.
      ref: https://doc.rust-lang.org/cargo/reference/semver.html#item-remove
     impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.40.0/src/lints/trait_missing.ron

Failed in:
trait hugr_core::hugr::rewrite::Rewrite, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite.rs:19
trait hugr_core::hugr::Rewrite, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/rewrite.rs:19
trait hugr_core::hugr::rewrite::simple_replace::HugrMutInternals, previously in file /home/runner/work/hugr/hugr/BASELINE_BRANCH/hugr-core/src/hugr/internal.rs:209

--- failure trait_removed_supertrait: supertrait removed or renamed ---

Description:
A supertrait was removed from a trait. Users of the trait can no longer assume it can also be used like its supertrait.
      ref: https://doc.rust-lang.org/reference/items/traits.html#supertraits
     impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.40.0/src/lints/trait_removed_supertrait.ron

Failed in:
supertrait hugr_core::hugr::rewrite::simple_replace::HugrMutInternals of trait HugrMut in file /home/runner/work/hugr/hugr/PR_BRANCH/hugr-core/src/hugr/hugrmut.rs:22

[lmondada]

bus factor considerations: we might want to fold RelRc into Hugr at some point (at least the parts that we care about), but I'd suggest first figuring out what works/if it works before putting efforts into that.