fix(qa): use active ASR provider in floating panel

[H-Chris233]

Summary

• Fixes the QA floating panel ASR path to use the configured active ASR provider instead of hardcoding Volcengine.
• Adds QA startup/transcription handling for Bailian realtime, Whisper-compatible batch providers, and local ASR providers while preserving existing QA UI/history behavior.
• Reuses the batch ASR chunk limit helper and scopes local ASR release guards by dictation vs QA session.

Root Cause

QA recording used its own Volcengine-only ASR handle and credential check, while normal dictation respected active_asr_provider. Users who configured another ASR provider could dictate normally, but the floating QA panel still tried the Volcengine path and surfaced the wrong provider error.

Test Plan

• cargo test --manifest-path "/home/chris233/openless/openless-all/app/src-tauri/Cargo.toml" qa_asr_provider_kind_tracks_active_provider -- --test-threads=1
• cargo test --manifest-path "/home/chris233/openless/openless-all/app/src-tauri/Cargo.toml" coordinator::tests --lib -- --test-threads=1
• cargo check --manifest-path "/home/chris233/openless/openless-all/app/src-tauri/Cargo.toml"
• git diff --check -- "openless-all/app/src-tauri/src/coordinator.rs" "openless-all/app/src-tauri/src/coordinator/dictation.rs"

Fixes #562