fix(analytics): preserve selected hash size in links

[n30nex]

Red commit: 5a5ecb6 (local browser: 14 passed, 8 behavior assertion failures before the fix).

Hash Issues links now restore bytes=1|2|3 for the selected control and its matrix/collision data. Missing or malformed values default to one byte. Selector clicks, section/top links, tab-bar changes, filters and theme refreshes retain the chosen view through the existing URL helper.

Fixes #1914.

• E2E assertion added: test-issue-1306-collisions-terminology-e2e.js:242. The existing CI-selected harness passes 23 checks, including distinct nonempty collision rows for each byte size. Its original assertions remain.
• Browser verified: http://127.0.0.1:55634 with the local fixture API, plus reviewed matrix/risk screenshots. Region refresh passed; area coverage skips because the fixture has no areas.
• Required frontend checks pass: 99 filter, 18 aging, 666 helpers; URL helpers pass 18. Three independent reviews found no blocking issues; their coverage suggestion is included in fb482fe.
• Added work parses URL state and updates six links. Rendering and bulk requests are reused; no backend, configuration, dependency or CI-list changes.
• A broader smoke run timed out at Live autocomplete (bug(live): node filter is oversized, ignores dark mode, no autocomplete, requires Enter + reloads page #1110); full-suite success is not established.

Preflight overrides

• The external run-all.sh is absent. Corresponding scope, PII, syntax, whitespace and CSS checks passed; no SQL, migration or image changes require those gates.
• Red browser evidence is local. Upstream CI execution remains a separate approval gate, as discussed in Maintainer availability: 45 open PRs, 183 open issues, nothing merged to master since 2026-07-18 #1922.

[efiten]

Merging. CI had never run on this (it was stuck in action_required, now approved for all seven of your PRs) and came back green.

The change is well contained and the details are right where they usually are not:

• The URL value is validated, not trusted. ['1','2','3'].includes(urlBytes) with a fallback to 1 means a hand-edited or truncated link cannot put the view into a state the server has no data for.
• history.replaceState only fires when the hash actually changes. Rewriting it unconditionally on every refresh is how a back button ends up useless.
• data-hash-section moves the section anchors along with the selection, so a shared "Hash Issues" link lands on the section the reader was looking at and the byte size they were looking at, rather than one of the two.
• URLState.updateHashParams is the existing shared helper (public/url-state.js:93), not a second implementation of hash editing.

Reading the byte size on every render rather than once at init is the part that actually fixes it: a tab switch, filter change or theme refresh re-renders, and the old refreshHashViews(1) silently reset the view each time. That is why this looked intermittent rather than broken.

eslint clean, frontend helper suite 666 passed 0 failed on your branch.