reqlan_context_model

Canonical composed context per context-model.ts.
Implementation: context-model.ts.
- context_focus is the single anchor ( idea, file, selection, or none ).
- context_dimensions each contribute context_contribution records with counts and summary lines.
- context_footprint merges enabled dimensions into deduped idea / file sets and an effective_center_id for graph / refs panes.
- current_file_slice is the projection used when the current-file lens is expanded. Includes `isRqFile`, `referencingIdeas`, `commentLinkedIdeas`, `folderReferencingIdeas`, and optional `gitChange`.
- context_selection when the user highlights a non-empty range spanning one or more `.rq` ideas ( selection_pane ).
- global_hop_depth and dimension_hop_control overrides on the model.
Host increments `revision` when any dimension or hop depth changes; webview ignores stale posts by revision.

Interactive page: reqlan_context_model