test(performance): count startup phases and SQL statements for the J1 launch journey

Implements plan item A2. With IPTVNATOR_PERF_CAPTURE=1 the main process
keeps named counters and registers a main-only performance:read-counters
IPC handler; without the flag nothing is counted and the handler does not
exist.

- debug-trace.ts owns the registry; traceStartupPhase replaces the
  trace('startup', ...) sites and counts main.startupPhases.
- The database worker counts executed statements through better-sqlite3's
  Statement prototype (the verbose callback expands every statement and
  made bulk inserts 2-4x slower) and posts the count over its message
  port, flushed before every other worker message. The main-thread shared
  connection is counted through a new connection observer in the shared
  database library.
- The first main window freezes main.modulesRegisteredBeforeWindow at
  creation and main.sqlStatementsBeforeReadyToShow at ready-to-show.
- The journey gate drops the ready-to-show that Electron emits for the
  about:blank detour, so the app sees the real document's first paint,
  and taps the counters handler; the J1 record reads both counters after
  the renderer probe completes.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/architecture/sqlite-db-worker.md

@@ -444,6 +444,24 @@ first, this receipt remains distinct from the later authoritative
 exposing the pending request. Disabled profiling performs no receipt clock or
 transport work, and `DatabaseWorkerClient.cancel()` remains fire-and-return.
 
+With `IPTVNATOR_PERF_CAPTURE=1`, the worker connection also counts the SQL
+statements it executes and posts `performance-sql-statements` messages that
+carry only a positive count, never SQL text or bound values. Counts are
+coalesced per microtask and flushed before every other worker message, so a
+response never overtakes the statements that produced it.
+`DatabaseWorkerClient` adds them to the main-process `main.sqlStatements`
+counter and settles nothing. Statements are counted by wrapping the
+execution methods of better-sqlite3's `Statement` prototype and the
+connection's `exec`, not through the `verbose` callback: a callback makes
+better-sqlite3 expand every statement's SQL, which made bulk inserts two to
+four times slower. A call that throws is not counted, which matches the SQL
+trace for statements that fail before execution. The main process counts its
+own shared connection the same way (`services/main-sql-statement-count.ts`,
+through the shared library's connection observer). Without the flag both
+connections are opened unchanged. See
+`workers/database-worker-sql-statement-count.ts` and
+[performance journeys](performance-journeys.md).
+
 ## Renderer Contract
 
 The preload bridge keeps the existing database methods but adds scoped worker