Remove recordings feature, replay sessions directly, bump to 0.6.0

Recordings were just a thin named pointer over an already-captured
session's events, so the whole separate feature (recordings table, API
routes, pages, UI) is gone: any completed session can now be named and
replayed directly. Replaying no longer creates a session or duplicates
events of its own - it just bumps the source session's playCount/lastPlayedAt.

Also renames play_sessions/playSession(s) to sessions/session(s) throughout
the schema, queries, API routes, and UI for consistency, and updates the
README to match the new flow.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

lib/db/queries/session-events.ts

@@ -11,14 +11,14 @@ export interface IncomingEvent {
   durationMs?: number;
 }
 
-export async function insertEvents(playSessionId: number, events: IncomingEvent[]): Promise<void> {
+export async function insertEvents(sessionId: number, events: IncomingEvent[]): Promise<void> {
   if (events.length === 0) return;
 
   const insertMany = sqlite.transaction((rows: IncomingEvent[]) => {
     for (const row of rows) {
       db.insert(sessionEvents)
         .values({
-          playSessionId,
+          sessionId,
           sessionDeviceId: row.sessionDeviceId,
           tsMs: row.tsMs,
           commandType: row.commandType,
@@ -33,10 +33,10 @@ export async function insertEvents(playSessionId: number, events: IncomingEvent[
   insertMany(events);
 }
 
-export async function getEventsForSession(playSessionId: number) {
+export async function getEventsForSession(sessionId: number) {
   return db
     .select()
     .from(sessionEvents)
-    .where(eq(sessionEvents.playSessionId, playSessionId))
+    .where(eq(sessionEvents.sessionId, sessionId))
     .orderBy(asc(sessionEvents.tsMs));
 }