feat: ship public site with SEO and visuals

Publish CMS content on public routes with responsive media,
accessibility checks, and deterministic visual baselines.

Co-authored-by: Cursor <cursoragent@cursor.com>

openspec/changes/build-public-site/specs/web-accessibility/spec.md

@@ -0,0 +1,68 @@
+## ADDED Requirements
+
+### Requirement: Public routes have no critical or serious accessibility issues
+
+The system SHALL run automated accessibility checks on the public routes covered by the browser suite (SPEC §6.5, §13.8). A critical or serious issue MUST fail the suite.
+
+#### Scenario: Critical issue blocks the suite
+
+- **WHEN** the automated accessibility check reports a critical or serious issue on a covered route
+- **THEN** the browser suite MUST fail and report the offending rule and selector
+
+#### Scenario: Covered routes are checked
+
+- **WHEN** the accessibility suite runs
+- **THEN** the home, services listing, portfolio listing and case detail MUST each be checked
+
+### Requirement: Public pages use accessible semantic structure
+
+Public pages SHALL provide semantic landmarks, exactly one `h1` per page, a coherent heading order, alt text on every content image, and visible focus on interactive elements (SPEC §6.5).
+
+#### Scenario: Single h1 per page
+
+- **WHEN** any public page is rendered
+- **THEN** exactly one `h1` element MUST be present
+
+#### Scenario: Landmarks are present
+
+- **WHEN** any public page is rendered
+- **THEN** `header`, `main`, `nav` and `footer` landmarks MUST be present
+
+#### Scenario: Content images expose alt text
+
+- **WHEN** a page renders a cover or gallery image
+- **THEN** the `alt` attribute MUST contain the stored alt text
+
+### Requirement: Public pages are fully keyboard operable
+
+Visitors SHALL be able to reach and activate every interactive element with the keyboard, with a visible focus indicator and a skip link to the main content.
+
+#### Scenario: Keyboard reaches the primary CTA
+
+- **WHEN** a visitor navigates the home with the Tab key
+- **THEN** the primary CTA MUST receive focus with a visible indicator
+- **AND** activating it with the keyboard MUST navigate to the contact route
+
+#### Scenario: Skip link bypasses navigation
+
+- **WHEN** a visitor focuses the first element of a public page
+- **THEN** a skip link to the main content MUST be available
+
+### Requirement: Reduced motion preference is honored
+
+The system SHALL suppress non-essential animation and transition when the user agent reports `prefers-reduced-motion: reduce`.
+
+#### Scenario: Reduced motion disables transitions
+
+- **GIVEN** the browser reports `prefers-reduced-motion: reduce`
+- **WHEN** a public page is loaded
+- **THEN** decorative transitions and animations MUST NOT run
+
+### Requirement: Public pages emit no console errors
+
+Covered public routes SHALL load without JavaScript console errors in a real browser (SPEC §13.8, §19).
+
+#### Scenario: Console stays clean on covered routes
+
+- **WHEN** a covered public route is loaded in the browser suite
+- **THEN** the console MUST contain no error-level messages