The user font-size preference applies CSS `zoom` on `<html>`
(see `composables/useFont.ts`). This breaks every popover that
anchors itself with `getBoundingClientRect()` + `position: fixed/absolute`,
because the rect is in visual pixels while CSS lengths are then
multiplied by zoom again — shifting popovers toward the lower-right
and miscomputing maxHeight / width / viewport-edge clamping.
PR #1459 patched only `AgentSelector.vue` (and left its width/maxHeight
unfixed). This PR introduces a shared helper `frontend/src/utils/zoom.ts`
(`getRootZoom`, `rectToCssPx`, `cssViewportSize`) and applies it to every
affected popover:
- `AgentSelector.vue` — refactored to use the helper; also normalizes
`width` and `maxHeight` (previously still in visual px).
- `Input-field.vue` — model dropdown, mention popup (typed @ and button-
triggered), and agent-mode dropdown.
- `KnowledgeBaseSelector.vue` — primary anchor path and fallback path.
- `UserMenu.vue` — tenant and IM floating submenus + viewport clamp.
- `FAQTagTooltip.vue` — fixed tooltip positioning + edge clamp.
- `AgentEditorModal.vue` — placeholder popups for system_prompt,
context_template, and rewrite/fallback prompts.
- `AgentStreamDisplay.vue` — `kb-float-popup` (absolute under body, also
under the zoom containing block).
Verified with `npm --prefix frontend run build`.
wizardchen
30332cca99