Integrate ASR/Omni fixes, API Route, Android IME and confirmation-based vocabulary learning. Complete settings transitions and macOS single-item credential storage. Synchronize all application versions to 2.0.0-Beta.4+build.20260930.
Integrated PRs: #1116, #1120, #1121, #1123, #1124, #1067 and #1128. Linux #1117 remains independent and is excluded from automatic release.
Validated: full cross-platform CI, 18 UI motion cases, 112 frontend test files, 1245 Core tests (1 ignored) and 572 macOS native tests.
Co-authored-by: HKLHaoBin <we3q@qq.com>
Consolidate the current 2.0 sidebar, overview, settings, vocabulary editing, correction rules page, and first-launch splash with their Core and Tauri adapters. Include the accompanying source and architecture documentation updates.
Validation: npm test (build and 73 discovered test files); cargo test -p openless-core --locked; Core/Linux and Tauri rustfmt checks.
