timely-v0.31.0

This release continues excising monomorphization sprawl from the progress subsystem: PortConnectivity's map becomes a sorted Vec, removing the last BTreeMap and HashMap from progress tracking (9.1% fewer LLVM lines on the bfs example), alongside clone and allocation trimming on hot paths.

Breaking changes

• PortConnectivity splits into a builder and a frozen reader, and Operate::initialize now returns the frozen form. This type is largely internal; the surface change is below. (#802, #804)

0.30	0.31
PortConnectivity::insert(i, e) -> bool	PortConnectivityBuilder::insert(i, e) (no return)
PortConnectivity::insert_ref(i, &e) -> bool	removed; build an Antichain and use add_port
PortConnectivity::add_port (panics on duplicate port)	PortConnectivityBuilder::add_port (merges duplicate)
tree: BTreeMap<usize, Antichain> field	gone; construct via PortConnectivityBuilder::freeze()
impl FromIterator for PortConnectivity	impl FromIterator for PortConnectivityBuilder
get, iter_ports	unchanged, on the frozen PortConnectivity
—	impl IntoIterator for PortConnectivity (new, consuming)

Other

• Removed all BTreeMap and HashMap from the progress subsystem: is_acyclic uses dense per-location in-degree counts, and summarize_outputs iterates semi-naively over binary-sized sorted runs. bfs example: 254,560 → 231,310 LLVM lines. (#802)
• Move rather than clone summaries in Tracker::allocate_from and Subgraph::initialize. (#804)
• Removed several clones on progress hot paths: Capability::drop, FrontierNotificator delivery, capture, Progcaster::recv, builder_raw. (#805)
• builder_rc trims the frontier/consumed/internal/produced bookkeeping vector capacities at build. (#806)