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>

app/api/sessions/[id]/route.ts

@@ -0,0 +1,56 @@
+import { NextResponse } from "next/server";
+import { z } from "zod";
+import { deleteSession, endSession, getSessionDetail, renameSession } from "@/lib/db/queries/sessions";
+import { withRouteLogging } from "@/lib/api/with-route-logging";
+
+const patchSchema = z
+  .object({
+    status: z.enum(["completed", "aborted"]).optional(),
+    name: z.string().min(1).max(160).optional(),
+    description: z.string().max(2000).optional(),
+  })
+  .refine((v) => v.status !== undefined || v.name !== undefined || v.description !== undefined, {
+    message: "at least one of status, name, description is required",
+  });
+
+export const GET = withRouteLogging(
+  "sessions.get",
+  async (_req: Request, { params }: { params: Promise<{ id: string }> }) => {
+    const { id } = await params;
+    const detail = await getSessionDetail(Number(id));
+    if (!detail) return NextResponse.json({ error: "not found" }, { status: 404 });
+    return NextResponse.json(detail);
+  },
+);
+
+export const PATCH = withRouteLogging(
+  "sessions.update",
+  async (req: Request, { params }: { params: Promise<{ id: string }> }) => {
+    const { id } = await params;
+    const parsed = patchSchema.safeParse(await req.json().catch(() => null));
+    if (!parsed.success) {
+      return NextResponse.json({ error: parsed.error.message }, { status: 400 });
+    }
+    const { status, name, description } = parsed.data;
+
+    let updated;
+    if (status !== undefined) {
+      updated = await endSession(Number(id), { status });
+    }
+    if (name !== undefined || description !== undefined) {
+      updated = await renameSession(Number(id), { name, description });
+    }
+
+    if (!updated) return NextResponse.json({ error: "not found" }, { status: 404 });
+    return NextResponse.json({ session: updated });
+  },
+);
+
+export const DELETE = withRouteLogging(
+  "sessions.delete",
+  async (_req: Request, { params }: { params: Promise<{ id: string }> }) => {
+    const { id } = await params;
+    await deleteSession(Number(id));
+    return NextResponse.json({ ok: true });
+  },
+);