Fix install script archive filename to include 'v' prefix - #15

…ndencyView, approve #15 plan

Clears all outstanding work so the graph-assembler-convergence (#15) starts on a clean tree.

#13 unify-subgraph-execution — complete:
- subgraph.go: deleted the action == nil structural execution path (replaced by a no-action error guard
  mirroring Node.Execute); NewSubgraph rejects action-less specs.
- flow/helpers.go + flow/provider.go: converged the child-walks onto walkSubgraphChildren; flow.Subgraph
  and flow.Gather both use it.
- activation_record.go: retry is now intrinsic to the single dispatch primitive DispatchChild
  (policy-driven attempts + ctx-cancellable backoff + ErrPaused/ctx.Err() short-circuit);
  flow.dispatchWithRetry deleted. Retry is impossible to bypass; gather bodies honor RetryPolicy.
- result_flow_test.go: structural control retargeted to TestBareNodeUnderRoot_FlowsLeafResult.
- doc-comment cleanups (structural -> by-name) across executable_unit/node/receipt/graph_executor/
  activation_record/trace/validate.

Dead code:
- removed pkg/op/dependencyview.go + dependencyview_test.go (orphaned synthesizer; a real dependency
  view will later be a filter over a graph/trace, per subgraph-result-flow follow-ups).

Plans:
- graph-assembler-convergence.md: approved, with NewGraph + LoadGraph sequence diagrams (NewGraph the
  sole &Graph{} builder; LoadGraph decodes -> assembleGraph -> NewGraph; graphMetadata threads the
  document's checksum/signature/schemaVersion/timestamp).
- unify-subgraph-execution.md: status updated through #13 completion.

Also sweeps in pre-existing cmd/lore builder.go + builder_test.go (detectPlatform -> platform.New;
#6-blocked). pkg/op + flow green (scoped); whole-tree still red on #6.

NewGraph and the load path now both prepare a root + metadata and call one private buildGraph -- the sole
place that hand-builds &Graph{} (Option B from graph-assembler-convergence.md).

- graph.go: + graphMetadata + buildGraph (sets fields from metadata, derives unitsByID, recomputes the
  checksum from CanonicalContent). NewGraph builds the root (populate derives edges) + fresh metadata,
  calls buildGraph, then signs the canonical via spec.SopsClient. NewGraphSpec inlines the canonical root
  (ID "root", binds flow.subgraph by name) -- the single root call site. LoadGraph decodes -> assembleGraph;
  assembleGraph (renamed buildGraphFromPayload) builds the root preserving the document's edges + metadata
  and calls buildGraph.
- node.go: assembleNode (renamed buildNodeFromPayload), below NewNode.
- subgraph.go: assembleSubgraph (renamed buildSubgraphFromPayload) + (*Subgraph).linkChildren moved in;
  NewRootSubgraphSpec deleted.
- helpers.go: resolvePayloadAction moved in.
- load.go: deleted.
- marshalers_test.go: + TestGraph_SaveLoad_RoundTrip_ChecksumPreserved (round-trips a non-derivable hand
  edge; asserts recomputed checksum == document's, edges/schemaVersion/timestamp intact).
- comment-only: validate_test.go, flow_announce_test.go, provider/flow/result_flow_test.go (stale
  NewRootSubgraphSpec mentions).

Root call-sites: 3 -> 1 (NewGraphSpec). Only buildGraph hand-builds &Graph{}. Semantic shift: load now
recomputes the checksum (an implicit integrity check) instead of copying the document's stored one.
pkg/op + flow green (scoped); whole-tree red on the out-of-scope #6 consumers.