fix(nodes): clearly mark the selected node in path chains

[n30nex]

Red commit: 0988bc0 (local browser: 3 passed, 8 behavior assertion failures before the fix).

The selected node now has a compact outline in long “Paths Through This Node” chains, in the side panel and full detail page. Matching uses complete public keys without case sensitivity; same-prefix siblings and unresolved hops stay unmarked. Existing links, escaped names, warnings and ambiguity underlines are preserved.

Fixes #1153. Its prerequisite #1144 is already merged.

• E2E assertion added: test-issue-1146-path-link-contrast-e2e.js:220. The existing CI-selected harness passes 11 checks across 18-hop paths, both themes, desktop/mobile, and the renderer fallback. Review follow-up bd8118f verifies the marked ambiguous hop's dashed underline.
• Browser verified: http://127.0.0.1:55635; desktop/mobile path screenshots were inspected. The broader smoke runner exited successfully with fixture-dependent skips.
• Required frontend checks pass: 99 filter, 18 aging, 666 helpers. CSS variables, seven CSS self-tests, 31 XSS sink checks, 17 XSS gate self-tests and XSS diff preflight pass.
• Three independent reviews found no blocking issues. Traversal remains linear with no new requests, settings, dependencies or cache invalidation; styling uses the existing customizer token.

Preflight overrides

• The external preflight runner is absent; corresponding scoped gates passed. Red browser evidence is local, with upstream CI approval tracked separately under the process in Maintainer availability: 45 open PRs, 183 open issues, nothing merged to master since 2026-07-18 #1922.
• Existing rapid-navigation map resize timer errors remain visible in browser logs and are outside this change.

[efiten]

Merging. CI had never run on this (stuck in action_required, now approved) and came back green.

The actual bug is the case comparison, and it is worth naming plainly: h.pubkey === n.public_key fails whenever the two sides differ in case, and both are hex strings arriving from different paths. So the "you are here" marker in a path chain silently did not appear for some nodes and did for others, which reads as a rendering quirk rather than a comparison bug. .toLowerCase() on both sides, hoisted out of the loop, fixes it.

Moving the inline font-weight/color onto a .hop-current class is the other half and it is not cosmetic: a contrast rule cannot be reviewed, themed or overridden while it lives in a style attribute.

Checked the combination rather than this PR alone: merged together with #1969 and #1970 onto current master it applies cleanly, the three touch disjoint hunks, eslint is clean and the frontend helper suite is 666 passed 0 failed. Three green PRs on one file are each green against a master that does not contain the other two, so that seemed worth confirming before merging any of them.