Fix tigrbl-lens white screen by loading CSS and upgrading to v0.0.7

[cobycloud]

Motivation

• The tigrbl Lens UI was rendering as a blank/unstyled page because the lens stylesheet was not being included in the generated /lens HTML.
• The tigrbl-lens client needed to be upgraded to the requested 0.0.7 release to pick up fixes and match the intended bundle.
• Tests should assert the presence of both the JS import and the CSS link so regressions are caught earlier.

Description

• Added a TIGRBL_LENS_VERSION = "0.0.7" constant and switched the importmap entry for @tigrbljs/tigrbl-lens to use that constant in build_lens_html.
• Injected the tigrbl-lens stylesheet link <link rel="stylesheet" href="https://esm.sh/@tigrbljs/tigrbl-lens@{TIGRBL_LENS_VERSION}/dist/tigrbl-lens.css" /> into the generated /lens HTML so the app is styled correctly.
• Updated the integration test test_mountable_lens_uvicorn.py to assert the new import map URL and to verify the CSS href is present in the HTML.

Testing

• Ran formatting and lint fixes with uv run --directory pkgs/standards --package tigrbl ruff format . and uv run --directory pkgs/standards --package tigrbl ruff check . --fix, and repeated for tigrbl-tests, all of which passed.
• Launched a uvicorn instance with mount_openrpc(..., path="/openrpc.json") and mount_lens(..., path="/lens") and confirmed GET /openrpc.json returns the OpenRPC JSON and GET /lens returns HTML containing the lens import and CSS link.
• Captured Playwright screenshots for /openrpc.json and /lens; Chromium failed to launch in this environment but the Firefox run completed and produced screenshots showing the OpenRPC JSON and the rendered Lens page.

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Codex Task