Reveal synthetic video text progressively

[mmkal]

Stacked on #15.

Synthetic text in rendered videos should read like typing:

• accepted prompt(...) values reveal one glyph at a time
• page.goto() destinations reveal progressively in the synthetic address bar
• long URLs use smaller type and stay within the address field

All effects happen during post-production. Playwright actions and raw recordings remain unchanged.

await page.goto("https://app.example.test/a/long/report/url");
page.once("dialog", dialog => dialog.accept("correct horse battery staple"));
await page.getByRole("button", { name: "Sign in" }).click();

Review media and validation will be added as implementation lands.

Coding agent session: 019fc7c1-8863-78c1-91fe-c101ea2f226a

[mmkal]

🤖 Superseded by #17, which carries the work on a fresh branch from latest main and targets main directly.