TUI: update version, add transaction/index/event views, fix hardcoded paths

[ElioNeto]

Problem

The TUI (src/bin/tui.rs) has several issues:

1. Stale version: Shows "ApexStore v2.1.0" — actual version is 2.2.0
2. Hardcoded data path: Uses ./.lsm_data instead of reading from config
3. No transaction support: Cannot begin/commit/rollback transactions
4. No TTL display: Keys with TTL show no expiry information
5. No secondary index browsing: No way to see or query indexes
6. No value search: Only prefix/substring search, no value-search mode
7. Limited pagination: SCAN/ALL/SEARCH show at most 20-30 results with no paging
8. No event viewer: Cannot subscribe to WebSocket/SSE events
9. Only uses "default" CF: No column family selector
10. No mouse scroll: Only click detection, no scroll-wheel for log panel

Request

Must have

1. Read version from Cargo.toml at build time (env!("CARGO_PKG_VERSION"))
2. Read data path from config file or env var, fall back to ./.lsm_data
3. Add TTL column to key-value list display when scanning
4. Increase result display limit and add page-up/page-down navigation for scan results

Nice to have

5. Add transaction management panel (begin/commit/rollback with status)
6. Add secondary index panel (create index, query by index, list indexes)
7. Add simple "subscribe to events" view that streams CDC events in log panel
8. Add column family selector (dropdown or tab)
9. Add mouse scroll support for log panel

Acceptance criteria

• Version displayed matches CARGO_PKG_VERSION
• Data path is configurable
• All existing functionality continues to work
• No new unwrap() calls in production code paths