[unohee]

Stacked on #12. This is phase 6 of the plan. The native driver is not at parity yet: the repo's own gates, run on it, found gaps (table below). The default driver does not change in this PR.

What

• Docs
  • README gets a "Drivers" section: what native is, what it does differently, and its measured status.
  • docs/VEGA_INTEGRATION.md describes the path without Playwright.
  • Measured: the native real-browser runs pass with playwright and patchright blocked from importing, and no Playwright module gets loaded.
• Gates can run on native
  • build_tools reads LYRA_BROWSER_DRIVER, and the gates that take --driver now accept native.
  • The downloads gate's temp-dir scan now also looks in native's parking dir. Without that, its "nothing left behind" checks passed on native without checking anything.
  • New: scripts/verify_native_parity_e2e.py.
• Fixes the gates found
  • IIFE evaluation: function vs. expression is now decided in the browser.
  • Focus emulation is set per page, so a key press reaches a page with nothing focused.
  • New: Page.aria_snapshot.
  • The download parking dir now follows TMPDIR.

CodeQL (python-security-and-quality)

[real defects in native code: 0 / noise: 41 under src/]

• Noise
  • 20 cyclic imports. Every reverse import is under TYPE_CHECKING; each module was imported on its own first to confirm.
  • A function import flagged as a mutable attribute.
  • A guarded raise and Protocol stub bodies, both in existing code.
  • Results from copies under worktrees/ and testing/.
  • Dev scripts that run loopback test servers.
• Tidied: two intentional empty except blocks now carry a comment, and one needless lambda is gone.
• Outside this change: uat/procs.py reads /proc files and leaves closing them to refcounting (minor).

Gates: native vs. playwright, both with the cdp guard (2026-10-23, Chrome 155, macOS)

gate	playwright	native
forms, wait, scriptredirect*	pass	forms and wait pass; scriptredirect stops at context.set_default_timeout
click	pass	stops at page.input_value (called by the gate itself)
downloads	pass	71 checks pass, then a download started by a popup is not seen
dialogs	pass	navigating away from a beforeunload page answers needs_approval
snapshot*	—	stops at page.content
click_refusal*	fails at check 3 (timeout)	67 checks pass, then the internal:control=enter-frame selector is unsupported
redirect_hop*	fails at POST 307	stops at context.set_default_timeout
browser, cdp_guard*	fail at "declared submission executes" (timeout)	fail earlier: a key press does not reach the page's keydown listener
tabs	fails (headful relaunch)	an unapproved popup leaves a tab open
motion	fails at "every batch loaded: 40"	the same check fails

* run with --driver native; the rest with LYRA_BROWSER_DRIVER=native. The Playwright failures in the table also happen without native: they are this machine's baseline.