/**
 * Security response headers middleware.
 *
 * Sets a baseline set of "no-brainer" security headers on every framework HTTP
 * response. These headers are layered defenses: each one mitigates a specific
 * class of attack, and together they harden the surface against MIME-sniffing,
 * referrer leakage, mixed-content downgrades, and cross-origin window/embed
 * access.
 *
 * The headers we emit:
 *
 *   - `Strict-Transport-Security` — forces HTTPS for the browser's lifetime
 *     of the cached value, preventing SSL-strip MITM. Only emitted when the
 *     request scheme is `https` (we don't want to break local-dev HTTP, and
 *     emitting HSTS over HTTP is a no-op per the spec but causes confusion).
 *   - `X-Content-Type-Options: nosniff` — disables browser MIME sniffing so
 *     a tool /render route serving user-authored HTML can't be misinterpreted
 *     as some other content type by a clever Accept header.
 *   - `Referrer-Policy: strict-origin-when-cross-origin` — strips path/query
 *     from outbound Referer headers when the request crosses origin, so a
 *     public-share viewer's outbound link clicks never leak the share token.
 *   - `Permissions-Policy: camera=*, microphone=(self), geolocation=(),
 *     screen-wake-lock=()` — allows microphone access for composer dictation
 *     and camera access for media-capture UI (the Clips recorder, and the
 *     Clips browser extension's camera bubble, which is injected as a
 *     cross-origin iframe and is therefore blocked outright by `camera=()`).
 *     Location and wake-lock stay disabled. The browser still gates actual
 *     camera/mic use behind a per-origin permission prompt, so `camera=*` only
 *     removes the policy-level block, not the user consent.
 *   - `Cross-Origin-Opener-Policy: same-origin` — isolates window.opener so
 *     a popup-window opener reference can't read or modify our document.
 *   - `Cross-Origin-Embedder-Policy: require-corp` — emitted only for
 *     validated MCP embed-session page loads and browser iframe navigations.
 *     COEP hosts such as Claude's MCP Apps proxy require framed cross-origin
 *     documents to opt in explicitly.
 *   - `Cross-Origin-Resource-Policy: same-site` — prevents other origins from
 *     embedding our endpoints as `<img>` / `<script>` / `<audio>`, blocking
 *     the simplest data-leak chain when combined with auth cookies. Validated
 *     MCP embed-session page loads and browser iframe navigations use
 *     `cross-origin` so COEP hosts can frame app documents.
 *
 * NOTE: `Cross-Origin-Embedder-Policy` is NOT set by default because it
 * requires every embedded subresource to opt in via CORP/CORS, which would
 * break Builder's iframe editor and template embed use cases. COOP + CORP
 * without COEP gives us most of the protection on normal responses; COEP is
 * only added for validated MCP embed-session page loads and browser iframe
 * navigations (see above).
 *
 * NOTE: `X-Frame-Options` is intentionally not set globally. Agent-native apps
 * are expected to run inside iframe hosts such as Builder, Design, and MCP app
 * shells. Routes that render especially sensitive iframe-only documents should
 * set their own route-specific CSP / frame policy.
 */
/**
 * Compute the sha256-<base64> hash token for an inline script's text content.
 * Pass the raw script body (no surrounding <script> tags). The resulting token
 * can be listed directly in a `script-src` CSP directive.
 */
export declare function computeInlineScriptHash(scriptContent: string): string;
/**
 * Create the security-headers h3 middleware. Mount this BEFORE other route
 * handlers so the headers are present on every response (including 4xx/5xx
 * error pages). Route handlers that need to tighten a specific header can call
 * `setResponseHeader` after this runs — the latest write wins.
 */
export declare function createSecurityHeadersMiddleware(): import("h3").EventHandlerWithFetch<import("h3").EventHandlerRequest, any>;
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