fix(tangle-cloud): drawer centering, connect-button gradient, topbar polish, italic suppression

[drewstone]

Round-3 fixes from a product critique

Four concrete defects + one cleanup, all triggered by real complaints on the last review:

1. Register button "weird centered panel" (0/10 → drawer)

The RegistrationDrawer renders as a Radix Dialog with side anchors (right-0 left-auto translate-x-0) so it should slide in from the right. My earlier wallet-modal centering fix applied --tw-translate-x: calc(-50% + sidebar/2) !important to every [role="dialog"], which dragged the drawer back to center.

Scope the centering rule to truly center-anchored dialogs only — selector now negates [class*="left-auto"], [class*="right-auto"], and [class*="translate-x-0"]. Side-anchored sheets keep their intended position; the wallet modal still gets sidebar-aware centering.

2. Connect button gradient (looked like staking dapp, not cloud)

tangle-cloud-wallet-action was forcing a hardcoded indigo-to-darker-indigo linear-gradient background. That was the only gradient in the cloud app — every other button uses sandbox-ui flat fills — so the Connect button always read as imported from a different system.

Strip the gradient. Use the same solid --btn-primary-bg fill as every other primary action. Height, padding, border-radius normalized to match sandbox-ui (36px / 6px / 14px padding).

Also drop the white-frosted wallet-mark tile (which existed only to make the wallet icon legible on the gradient).

3. Topbar buttons (mismatched heights, different surfaces)

Network selector, theme toggle, transactions, and connect were each styled differently — Connect had a tinted background, others had different alpha. Unified all topbar buttons to the same shape: 36px / 6px / transparent / 1px border / var(--bg-hover) on hover.

4. Italics on dark backgrounds (dark on dark, unreadable)

Browser italic-synthesis was firing when a requested weight wasn't in the loaded Geist font face. Force font-style: normal on every interactive element under .tangle-cloud-shell (button / a / span / p / h1-h6) — .italic class still opts in explicitly for the rare deliberate use.

5. Drop the breadcrumb header noise

Cloud / Blueprints / Details told the operator nothing the sidebar + page H1 weren't already conveying. The auto-generated leaf ("Details", "Service", "Manage") was generic enough to actively mislead on iframe pages. Replaced the breadcrumb row with an empty slot reserved for future global controls (search, branch picker, etc.).

Test plan

• yarn nx typecheck/lint/test/build tangle-cloud — clean (162/162 tests, 2 pre-existing warnings, 0 errors)
• Local: connect modal opens with MetaMask + Coinbase + WalletConnect instead of just "Injected"
• Local: clean topbar — no gradient, no italics, no breadcrumb
• Visual confirmation in screenshots: connect button is solid primary (was indigo gradient), topbar buttons are uniform ghost surface, breadcrumb is gone
• After merge + deploy: verify register drawer slides in from the right (not centered) on develop.cloud.tangle.tools when clicking Register on a blueprint card