Align fork with upstream: adopt src/ base, force-exclude cloud/telemetry, port recorder

[wbogusz-poolside]

Why

Our fork branched from browser-use/browser-harness back around PR browser-use#190 and added the polling Recorder, but upstream has moved 273 commits ahead since — it restructured into a src/ package, hardened the daemon and helpers, and fixed real bugs we still carry (e.g. current_tab() returning the browser-level target instead of the page, js() silently swallowing errors, a PID-reuse race in restart_daemon). This re-founds our fork on that newer base and re-applies our poolside delta on top, so we pick up the fixes and packaging while keeping our own identity and staying strictly local — no cloud, no telemetry.

Note on the base: this PR targets will/upstream-base (pinned at upstream/main @ 4d75f11), so the diff below is exactly our poolside delta, not the 273-commit upstream import. Adopting it re-points our fork onto that newer upstream base.

What

• Re-founded on upstream's src/browser_harness/ layout (branch based on upstream/main @ 4d75f11).
• Restored the browser-harness skill identity (frontmatter name + H1) and re-added the Recording Axiom section to SKILL.md.
• Switched all docs/invocation from the retired -c flag to stdin (browser-harness < file.py / <<'PY' … PY), including install.md, interaction-skills/profile-sync.md, and domain-skill examples.
• Force-excluded cloud + telemetry in code (not just via config):
  • __init__.py hard-sets BH_TELEMETRY=0 and drops BU_AUTOSPAWN in-process, so exclusion holds even if an env var says otherwise.
  • run.py removes the telemetry capture call, the cloud auto-bootstrap block (now a bare ensure_daemon()), the PyPI update banner, and the auth / telemetry CLI + script surface.
  • run_doctor no longer calls PyPI or shows a cloud-auth row; the daemon handshake error no longer references Browser Use Cloud.
  • Deleted the browser-use-cloud domain skill.
  • Added tests/unit/test_no_egress.py — a contract test asserting no outbound calls to PostHog / Browser Use Cloud / PyPI, that the forced telemetry-off beats an explicit BH_TELEMETRY=1 opt-in, that cloud bootstrap cannot fire even with BU_AUTOSPAWN=1 + a key, and that cloud names are absent from the script/CLI surface.
• Preserved the poolside console skill-ingestion contract (the reason skills/browser-harness/ exists as its own directory):
  • The console scans the repo for **/SKILL.md, skips symlinks on upload, and requires the SKILL.md's parent directory name to equal its frontmatter name. Upstream made skills/browser-harness/SKILL.md a symlink to the repo-root file, which would have silently failed to register (and a root-level or src/browser_harness/-nested SKILL.md can never match the contract). Inverted the symlink direction so the real file lives at the discoverable skills/browser-harness/SKILL.md, with the repo-root and packaged (src/browser_harness/) copies pointing to it — DRY preserved, content byte-identical.
  • Made the delivered skill self-contained: the console tars the whole skills/browser-harness/ dir, so bundled the 17 guides SKILL.md lists into skills/browser-harness/interaction-skills/ (real files) and switched its two github.com/poolsideai URLs to relative paths (references/install.md, interaction-skills/). No runtime fetch; profile-sync.md intentionally excluded (remote-sync doc).
  • Added tests/unit/test_skill_bundle.py guarding that the discoverable SKILL.md stays a real file, references no fetch URLs, and that every listed guide is bundled and byte-identical to the canonical interaction-skills/ copy.
  • Removed upstream's .claude-plugin/ marketplace files (a separate Claude Code plugin mechanism) which still referenced "Browser Use cloud" and the Browser Use identity.
• Ported the polling screenshot Recorder (src/browser_harness/recording.py), exposed in script globals, with the recording interaction skill and tests.
• Re-applied the session_id() / set_session() helper wrappers.
• Declared the imageio-ffmpeg encoder dependency in pyproject.toml (kept upstream's websockets==15.0.1 pin and pillow).
• Left auth.py / telemetry.py dormant on disk (unreferenced from the CLI/script surface) rather than deleted, to minimize conflicts on future upstream syncs — the in-process guard and the no-egress test keep them inert.