perf: consolidate three getState() calls into single await in resolveWebviewView

[roomote]

This PR attempts to address Issue #11319 by consolidating three separate this.getState().then(...) calls into a single await this.getState() with destructuring in resolveWebviewView().

Changes

• Replace three independent this.getState().then(...) calls (terminal settings, ttsEnabled, ttsSpeed) with a single await this.getState() and destructuring
• Same defaults preserved: terminalShellIntegrationTimeout = Terminal.defaultShellIntegrationTimeout, ttsEnabled ?? false, ttsSpeed ?? 1, etc.
• No behavioral change -- same setter calls, same values, same error propagation

Why

• Eliminates ~2 redundant async getState() executions during view activation
• Ensures a single consistent settings snapshot (avoids potential inconsistency if state changes mid-resolution)
• resolveWebviewView is already async, so await is idiomatic here

Test plan

• All ClineProvider tests pass (88 passed, 6 skipped in main spec; 52 passed across related specs)
• Lint: 14/14 passed
• Type check: 14/14 passed

Closes #11319. Feedback and guidance are welcome.

---

Important

Consolidates multiple getState() calls into a single await with destructuring in resolveWebviewView() of ClineProvider.ts, improving performance and consistency without changing behavior.

• Behavior:
  • Consolidates three this.getState().then(...) calls into a single await this.getState() with destructuring in resolveWebviewView() in ClineProvider.ts.
  • Preserves defaults: terminalShellIntegrationTimeout, ttsEnabled, ttsSpeed, etc.
  • No change in behavior: same setter calls, values, and error handling.
• Performance:
  • Reduces redundant async getState() calls from three to one.
  • Ensures consistent settings snapshot during view activation.
• Misc:
  • resolveWebviewView remains async, aligning with idiomatic usage.

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[roomote]

Rooviewer   See task

Review complete. No issues found. The consolidation of three fire-and-forget getState().then() calls into a single await getState() with destructuring is correct -- all defaults, nullish coalescing, and setter calls are preserved.

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