fix: env variable overwrite and action menu clipping in create function wizard

[HarshMN2345]

Summary

• Env variable overwrite bug: In the Create function wizard, variables are stored client-side with no `$id` (not yet saved to the API). The update modal matched variables by `variable.$id === selectedVar.$id` — since all unsaved variables have `$id === undefined`, every variable matched and got overwritten with the edited one's values. Fixed by falling back to key-based matching when `$id` is absent.

Root cause

`updateVariableModal.svelte` line 25:
```js
// Before — undefined === undefined matches ALL unsaved variables
if (variable.$id === selectedVar.$id) { return pair; }

// After — fall back to key match when no $id exists
const match = selectedVar.$id
? variable.$id === selectedVar.$id
: variable.key === selectedVar.key;
return match ? pair : variable;
```

Test plan

• Create function wizard: add 3 variables with different keys/values, edit one → only that variable should change
• Existing saved variables (with `$id`) still update correctly via the function settings page

[greptile-apps]

Greptile Summary

This PR fixes two bugs in the Create Function wizard's variable management: the updateVariableModal now matches unsaved variables by key instead of $id (preventing all-variables overwrite), and a new variableActionMenu component portals the action menu to document.body via floating-ui to escape the accordion's overflow context.

• updateVariableModal.svelte: The fix correctly falls back to variable.key === selectedVar.key when selectedVar.$id is absent; the modal is rendered inside {#if showUpdate} so pair always re-initialises from the current selectedVar, keeping the fix sound.
• variableActionMenu.svelte: A hand-rolled portal + floating-ui dropdown replaces the Popover component; the autoUpdate cleanup is assigned to a module-level cleanup variable rather than returned from $effect, leaving scroll/resize listeners attached if the component is destroyed while the menu is open (noted in a prior review round).
• environmentVariables.svelte: Delegates the ... action cell to VariableActionMenu; adds max column-width constraints and an icon-only mode for the Create button on small viewports.

Confidence Score: 4/5

The env-variable overwrite fix is correct and self-contained. The new variableActionMenu component ships with an unresolved autoUpdate cleanup gap that can leave stale event listeners when a row is removed while the menu is open.

The matching-logic fix in updateVariableModal is correct and low-risk — the modal is always destroyed and re-created, so pair initialises fresh on every open. The variableActionMenu replacement works well in the common path, but the autoUpdate cleanup is stored in a module-level variable rather than returned from the $effect, meaning Svelte cannot invoke it on component teardown when open is still true.

src/lib/components/variables/variableActionMenu.svelte — specifically the $effect at line 47 that manages the autoUpdate lifecycle.

Important Files Changed

Filename	Overview
src/lib/components/variables/updateVariableModal.svelte	Core bug fix: falling back to key-based matching when $id is undefined (unsaved wizard variables) correctly prevents all-variables overwrite; logic is sound since the modal is destroyed/recreated via {#if showUpdate} so pair always initialises fresh.
src/lib/components/variables/variableActionMenu.svelte	New custom portal component using floating-ui; fixes overflow/clipping; the autoUpdate cleanup is stored in a module-level variable rather than returned from the $effect, so listeners leak when the component is destroyed while the menu is open (flagged in a prior review round).
src/lib/components/variables/environmentVariables.svelte	Replaces inline Popover + ActionMenu markup with the new VariableActionMenu component; adjusts column widths to add max constraints; adds icon-only mode for the Create button on small viewports. Changes look correct.

_{Reviews (9): Last reviewed commit: "fix: remove stopPropagation so outside-c..." | Re-trigger Greptile}