Decode packed event records for runtime import

docs/runtime-rehost-plan.md

@@ -22,11 +22,12 @@ Implemented today:
 - snapshots, state dumps, save-slice projection, and normalized state diffing already exist in the
   CLI and fixture layers
 - checked-in runtime fixtures already cover deterministic stepping, periodic service, direct trigger
-  service, snapshot-backed inputs, and normalized state-fragment assertions
+  service, snapshot-backed inputs, normalized state-fragment assertions, and imported packed-event
+  execution
 
 That means the next implementation work is breadth, not bootstrap. The recommended next slice is
-the `.smp` event-collection structural bridge across inspection, save-slice loading, import, and
-snapshot-backed fixtures.
+captured-runtime depth plus wider packed-event target-family coverage, not another persistence
+scaffold pass.
 
 ## Why This Boundary
 
@@ -215,10 +216,12 @@ Current status:
 
 - runtime snapshots and state dumps are implemented
 - `.smp` save inspection and partial save-slice projection already feed normalized runtime state
-- the packed event-collection summary now survives into loaded save slices and projected runtime
-  snapshots, but per-record packed bodies are still deferred
-- the remaining gap is broader captured-runtime and round-trip fixture depth plus deeper `.smp`
-  event-body decoding, not the first persistence surface
+- the packed event-collection bridge now carries per-record summaries into loaded save slices,
+  projected runtime snapshots, normalized diffs, and fixtures
+- the first decoded packed-event subset can now import into executable runtime records when the
+  decoded actions fit the current normalized runtime-effect model
+- the remaining gap is broader captured-runtime and round-trip fixture depth plus wider packed
+  target-family coverage, not first-pass packed-event decode
 
 ### Milestone 4: Domain Expansion
 
@@ -347,8 +350,8 @@ The currently implemented normalized runtime surface is:
   `runtime summarize-state`, `runtime import-state`, and `runtime diff-state`
 - deterministic stepping, periodic trigger dispatch, one-shot event handling, dirty reruns, and a
   normalized runtime-effect vocabulary with staged event-record mutation
-- save-side inspection and partial state projection for `.smp` inputs, including the structural
-  packed event-collection summary
+- save-side inspection and partial state projection for `.smp` inputs, including per-record packed
+  event summaries and selective executable import
 
 Checked-in fixture families already include:
 
@@ -360,33 +363,35 @@ Checked-in fixture families already include:
 
 ## Next Slice
 
-The recommended next implementation slice is deeper `.smp` event persistence, starting from the
-structural bridge that already exists today.
+The recommended next implementation slice is broader captured-runtime depth on top of the packed
+event bridge that now exists today.
 
 Target behavior:
 
-- keep carrying the packed event collection across `inspect-smp`, `load-save-slice`,
-  `import-save-state`, snapshots, diffs, and fixtures
-- deepen that bridge from collection structure into per-record packed-body summaries
-- preserve the separation between parity-shaped packed state and executable normalized runtime state
-  until the packed layout is better decoded
+- keep the packed event bridge grounded against real captured save inputs rather than only synthetic
+  parser tests and snapshot fixtures
+- expand the executable import subset beyond the current direct-state and follow-on lanes only when
+  target resolution and field semantics are statically grounded enough to preserve headless
+  determinism
+- keep preserving unsupported packed rows as parity summaries instead of guessing executable meaning
 
 Public-model additions for that slice:
 
-- packed per-record event summary types on the `.smp` side
-- optional runtime-side parity summaries for imported packed event records
-- no new executable `RuntimeEffect` variants by default in that slice
+- additional captured-save fixture material for packed event collections
+- wider target-family summaries only where imported execution can be justified by current static
+  evidence
+- no shell queue/modal behavior in the runtime core
 
 Fixture work for that slice:
 
-- one or more snapshot-backed fixtures that prove imported packed event state survives normalize and
-  diff paths
-- synthetic report/save-slice tests that lock the first per-record packed-body parse shape
-- state-fragment assertions that lock imported collection ids, version, and record counts
+- captured `.smp` or save-slice-backed fixtures that prove real packed event records survive import
+  and diff paths
+- regression fixtures that lock the current selective executable import boundary
+- state-fragment assertions that lock both packed parity summaries and imported executable records
 
 Do not mix this slice with:
 
 - territory-access or selected-profile parity
 - placed-structure batch placement parity
 - shell queue/modal behavior
-- direct translation of packed RT3 event rows into executable normalized effects
+- broad speculative translation of packed RT3 event rows into executable normalized effects