Fix Summary — Issues #63, #64, #66, #67, #68

Issue #63 — deploy.sh strict-mode and CLI validation

Changed: tests/deploy-script-regression.sh

The deploy.sh already had all required guards (livereload guarded branch, IPv6 URL bracketing, port/host validation). Added the missing smoke-test cases to tests/deploy-script-regression.sh:

test_missing_port_argument_is_rejected — --port with no following value
test_port_flag_as_value_is_rejected — --port --drafts (flag as value)
test_missing_host_argument_is_rejected — --host with no following value
test_nonnumeric_port_is_rejected — --port abc

Test result: deploy-script regression tests passed (9 scenarios, all pass)

Issue #64 — validate-content-rules fail-fast for missing files / bad headings

Changed: scripts/validate-content-rules.sh

Updated require_file error message to the specified format: "file not found: <path>".
Fixed check ordering in validate_history_order: year-context presence is now asserted before the month-name validity check, so a heading that appears before any ## YYYY heading always gets the “appears before any year heading” diagnostic rather than being swallowed by an “invalid month name” error.
Improved all three history-parsing error messages to include the full offending heading text and surrounding context.

Test result: ✓ Content ordering and research tag rules passed.

Issue #66 — Non-standard CSS selectors and design-token correctness

Changed: assets/css/command-palette.css, assets/css/teaching.css, assets/js/command-palette.js

command-palette.css: Replaced the non-standard :has(.command-palette-section-title:contains("Search Results")) selector with the class .command-palette-section--search-results.
command-palette.js: renderSections now sets the command-palette-section--search-results class on the section element when the section name is "Search Results".
teaching.css: Replaced four :contains("Course Schedule") rules with:
- .course-schedule-heading (for the preceding h2), and
- explicit .schedule-container h3 / h4 / ul rules (the .schedule-container wrapper already existed in templates).
teaching.css: Corrected two wrong CSS custom-property fallback values:
- var(--color-heading-h2, #ff6b6b) → var(--color-heading-h2, #0156b3) (#ff6b6b was a red fallback for a blue token)
- var(--color-heading-h3, #000) → var(--color-heading-h3, #333) (matches the light-mode definition in styles.css)

Issue #67 — Teaching markdown CI gate scope

Changed: .github/workflows/teaching-content-checks.yml, CLAUDE.md

Added assets/images/teaching/README.md to the paths triggers for both pull_request and push events so changes to that file fire the workflow.
Extended both markdownlint-cli2 and prettier --check invocations to include assets/images/teaching/README.md alongside _teaching/**/*.md.
Documented the equivalent local one-liner in the Essential Commands section of CLAUDE.md.

Issue #68 — Stale async search results in command palette

Changed: assets/js/command-palette.js, tests/command-palette-stale-search.test.js (new)

Added a _searchToken monotonic counter at module scope. Each call to renderCommandResults captures the current token value. The async SearchManager.searchForCommandPalette callback checks token !== _searchToken before updating the DOM; if a newer search has been issued it returns without rendering, eliminating stale-result overwrites.
Exposed window._getSearchToken() for test introspection.
Added tests/command-palette-stale-search.test.js with three behaviour- focused regression scenarios:
1. Stale first result is discarded when a second search is still in-flight.
2. Single in-flight search resolves and renders normally.
3. Stale result resolves after the current result — DOM is unchanged.

Test Results

Suite	Result
`jest` (all 9 suites, 51 tests)	PASS
`tests/deploy-script-regression.sh` (9 scenarios)	PASS
`scripts/validate-content-rules.sh`	PASS