ci: add weekly selector health canary for x.com bundle identifiers

[digitalby]

Why

Twitter/X silently rotates data-testid values. Today breakage is only caught when a hotkey stops working and gets reported. This adds an automated canary that fires when the x.com bundle stops shipping identifiers tied to the selectors our userscripts depend on.

What

• tools/selector-health/ -- Playwright loads https://x.com/jack/status/20 (a public status URL; the login-walled x.com/ root is missing most SPA chunks), captures every JS response, and greps for proxy identifiers listed in selectors.json.
• .github/workflows/selector-health.yml -- runs weekly (0 9 * * 1), on workflow_dispatch, and on push to main when the tool or workflow file changes. On failure it opens, or edits if already open, a single rolling Selector health check failing issue via gh.

Honest scope

The object-literal form "data-testid":"X" does not appear in the compiled bundle because React sets testIDs dynamically via props. Only [data-testid="tweet"] survives as a literal, thanks to Twitter's own querySelector call. Everything else is tracked via proxy identifiers (TWEET_CARET, QuoteTweet, UserCell, appBarBack, UserName, UserAvatar-Container-, retweet, unretweet).

This catches structural renames and feature removals. It does not catch a silent data-testid rename where the component keeps its name. Documented in tools/selector-health/README.md.

Verification

Local run: 9/9 needles pass with counts 1 to 274 against thresholds 1 to 10. Corruption test: swapping TWEET_CARET for a bogus string produces exit 1 with the correct missing-selector report.

OK  [critical] tweet-article            hits=1/1
OK  [critical] three-dot-menu           hits=3/1
OK  [high]     app-bar-back             hits=12/3
OK  [high]     user-name                hits=54/10
OK  [high]     user-avatar-container-   hits=1/1
OK  [high]     quote-tweet              hits=98/10
OK  [high]     user-cell                hits=13/5
OK  [medium]   retweet                  hits=274/10
OK  [medium]   unretweet                hits=22/3

CI cannot run until merged because workflow_dispatch and path-filtered push require the workflow file to exist on the default branch.

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Wait for bundle reads before closing the browser

The script closes Chromium immediately after navigation, but bundle collection happens in an async page.on('response') handler and those response.text() reads are never awaited. On slower or larger JS responses, closing the context can make response.text() fail, and the catch block silently drops those bundles, which undercounts needles and can trigger false critical/high failures in CI. Track pending response-read promises and await them before closing the browser.

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