Release v0.1.1: mixed-key truth + microphone readiness fixes

[sammargolis]

Summary

This PR prepares v0.1.1 with production fixes for mixed-mode key validation and desktop microphone reliability.

Included fixes

• Use server/env truth for Anthropic key status (prevents false mixed-mode key blocker).
• Add GET /api/settings/mixed-auth-status and wire UI gating to it.
• Add strict microphone readiness checks (real capture + signal sampling).
• Add mic permission recovery UX (open microphone settings, diagnostics, retry flow).
• Add preferred microphone device persistence and fallback to system default when saved device is stale.
• Improve transcription error classification and messaging (blank audio vs mic permission/signal).
• Add macOS audio-input entitlement in packaging (com.apple.security.device.audio-input) for app + helpers.

Validation run

• pnpm -s build:test
• pnpm -s test:e2e:desktop:ipc
• pnpm -s test:e2e:desktop:launch
• pnpm -s build:desktop

Release impact

• Fixes missing/blocked microphone prompt behavior in packaged mac builds.
• Fixes false "Anthropic key required" modal when key is already configured in server/env.