[S-001] adaptive-fetch returns backend API JSON instead of SPA page content

[lidge-jun]

adaptive-fetch on SPA URLs (ChatGPT, Next.js) returns raw backend API JSON instead of rendered page content.

Root cause: isAuthEndpoint() misses /backend-api/*, content-scorer gives high scores to JSON blobs, browser-escalation waits only 300ms.

Fixed in commit 3edd046: added isSpaInternalEndpoint filter, JSON blob score penalty, and waitForSpaContent polling.

[lidge-jun]

Fixed in PR #107