feat(host): inject parameters into execution snapshots

[shipyard-local]

Summary

Adds a generic, snapshot-scoped SignalGraph::ExecutionSnapshot::inject_parameter_events (routing through a shared static helper) so exact per-block parameter events can be injected against a prepared execution snapshot the same way the public SignalGraph::inject_parameter_events does against the live graph. Both take only generic NodeId + state::ParameterEventQueue — no coupling to any higher layer.

This is the generic ingress the timeline host-delivery layer will call; the delivery code stays a caller, never a friend. First host slice of Gate 5, stacked on the merged playback compiler+renderer slices.

Surgical + generic (no B2 friendship)

Deliberately additive on the shared signal_graph: +3 hpp (helper decl), +24 cpp (the shared helper), +3 execution_snapshot.hpp (the new generic method). Zero friend declarations, zero Timeline coupling — verified. The RT-exact claim path + its passkey is the separate host-delivery PR.

Tests

test_host_signal_graph.cpp +71: exercises the generic snapshot-inject path (a non-Timeline caller injecting via ExecutionSnapshot). pulp-test-host-signal-graph 7501 assertions / 113 cases. Broad Release build all-targets green.

🤖 Generated with Claude Code

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🔎 Provenance

Agent	claude
Machine	m3
Tab	Timeline v3
Directory	/Volumes/Workshop/Code/pulp-g5
Session	c66f4a64-25ea-42e5-b184-d48611a066a2

Resume

claude --resume c66f4a64-25ea-42e5-b184-d48611a066a2

Jump to this tab

cmux surface focus C0B3DA54-39AF-4DAA-8089-AA08DAB71968

Relaunch (any agent)

cmux surface resume get --surface C0B3DA54-39AF-4DAA-8089-AA08DAB71968

Restore URL — https://claude.ai/code/session_01TVQHcnbg3t6TvXsdv6gXhS

_{stamped 2026-07-22 22:34 UTC}