JS linting round 3: fix remaining no-undef findings #1588

[davmlaw]

🤖 Written by Claude

Addresses #1588 (stacked on #1585 — diff shows only this round's changes).

Triages all 149 remaining no-undef warnings: ESLint is now clean apart from the 29 intentionally-kept errors (json2csv.js, include_jqgrid.js, global.js debounce, phenotype.js).

Bug fixes

• citations.js: error-branch abstract appended to undefined detailContainer → citDom
• datatable_definition.js: $(separator) → $(settings.separator) in TableFormat.combine
• vc_form.js: removed dead switch assigning unused undeclared icon

Missing local declarations (added const/let, verified no cross-file/template readers): flags.js, vc_form.js, vc_diff.js, panel_app.js, venn_intersect.js, analysis_nodes.js, datatable_definition.js

Shared state given a proper home

• eKeysBase → declared in VCForm IIFE scope beside eKeys
• SIDE_LENGTH / DEFAULT_SHADOW_COLOR → top-level const (samplenode.js is page-loaded everywhere)
• EMPTY_LINK → top-level const (note: currently unused, deletion candidate)
• Fragment-file cross-execution state (seen_igv_error, RAISED_GET_ANALYSIS_WINDOW_JS_ERROR, VENN_TOGGLE_WIDGET_CLASS, venn_id, freq) kept as plain assignments, declared writable in eslint.config.mjs

eslint.config.mjs: declared cross-file first-party functions and template-injected globals (analysis.html and related), each annotated with its defining file.

All touched files pass node --check.

🤖 Generated with Claude Code