feat: ship VidXP application platform and release channels

[tulayha]

Summary

• add the durable VidXP application core for managed media, atomic indexes, background jobs, artifacts, and grounded video queries
• expose the same product through the CLI, browser interface, Python and HTTP APIs, and MCP
• add the managed Tauri desktop application, tray lifecycle, guided runtime/model setup, and unsigned native installers
• publish local, control, and CPU-worker container profiles for direct GHCR and server/Coolify deployment
• replace the failed single-branch release automation with main beta releases, release stable promotion, component-aware Release Please PRs, and an automatically maintained promotion PR
• make publication resumable without silently accepting conflicts: PyPI/TestPyPI require exact filename and SHA-256 matches, while existing GHCR version tags must belong to the same source revision
• rewrite the README and installation guide around product capabilities and the three intended entry points: CLI/MCP, desktop, and published server containers

Release flow

• main remains the default integration branch and publishes beta component releases
• release receives approved promotion PRs and publishes stable component releases
• stable publication must complete its package, container, desktop, and GitHub release gates before main can be fast-forwarded from release
• Python/core, desktop, and container work is path- and component-scoped; pull requests do not run every Python/OS/desktop build combination
• failed publication can resume the same immutable version only when the public registry state matches the locally rebuilt artifacts

Validation

• uv sync --frozen --extra all --extra frontend --extra benchmarks --extra server --extra slm --extra test --no-dev
• ruff check src tests
• full Python suite: 469 passed, 3 skipped
• optimized Rust/Tauri suite: 8 passed
• npm ci: 0 vulnerabilities
• all 11 workflow files passed Actionlint 1.7.12
• beta and stable Release Please configs passed the official schema and Release Please 17.11.0 remote dry-runs
• wheel and normalized source distribution reproduced byte-for-byte across two builds
• Docker Compose configuration passed; a local image smoke was not claimed because Docker Desktop was not running on this machine (the publication workflow builds and smokes all three images before pushing)