style(web): fix inconsistencies in new settings layouts

[extoci]

Summary

Fix inconsistencies in settings:

(human written note: for some of the images in "before" i used max contrast to make it more visible, my agent did not when capturing after screenshots, this is not a regression)

Screenshots

Before (weird unnecessary left padding on Start form Origin):

After:

Before (rounded borders on non-edge items in Source Control & Remote Environments):

After:

Codex, GPT-6 via T3 Code, on behalf of Exotic.

Note

[!NOTE]

Remove rounded corners and responsive padding from settings row layouts

• Removes rounded-corner utilities from endpoint rows, discovery item rows, source-control skeleton rows, and the shared ITEM_ROW_CLASSNAME in itemRows.ts
• Removes responsive left-padding from the start-from-origin setting row in GeneralSettingsPanel within SettingsPanels.tsx
• Updates ITEM_ROW_CLASSNAME documentation to describe parent-owned borders and separators
• Risk: settings rows now render with square corners; visual regression possible in any out-of-tree consumers of ITEM_ROW_CLASSNAME or ENDPOINT_ROW_CLASSNAME

^{Macroscope summarized 291bb58.}

[macroscopeapp]

Approvability

Verdict: Would Approve

Macroscope's review found this PR approvable — This is a small, self-contained settings UI cleanup that changes only row corner styling and documentation. It does not affect product defaults, application logic, data handling, APIs, or static-analysis configuration.

Not approved because:

• Monthly spending limit reached (workspace setting). Approvability relies on correctness review in order to determine eligibility

^{Review your spending limits in Billing settings. You can add or adjust custom eligibility rules. Learn more.}

Dismissing prior approval to re-evaluate 2e683d8

Dismissing prior approval to re-evaluate 8d93ec0

[extoci]

note: i reverted this last change because i think codex just messed up lol

Dismissing prior approval to re-evaluate ef21161