fix: guard json.loads against non-JSON HTTP responses

[annguyenNous]

Problem

Multiple tools and gateway adapters parse HTTP responses with json.loads() without catching json.JSONDecodeError. When servers return non-JSON bodies (HTML error pages, 502 gateways, empty responses), these crash with unhandled JSONDecodeError.

Fix

Add json.JSONDecodeError guards to 5 files across tools/ and gateway/:

File	Issue	Fix
tools/osv_check.py:151	OSV API response — no try/except	Wrap in try/except, return [] on invalid JSON
tools/discord_tool.py:90	Discord API — only catches HTTPError	Add JSONDecodeError to except clause
tools/browser_cdp_tool.py:143,177	Chrome CDP WebSocket frames — bare json.loads	Wrap in try/except, continue on malformed frames
gateway/platforms/api_server.py:377	SQLite response cache — bare json.loads + possible None row[0]	Add None check + try/except, return None on corrupt data
gateway/platforms/weixin.py:386,406	iLink API helpers — bare json.loads	Wrap in try/except, raise RuntimeError with context

Tests

• All 14 modified files pass py_compile syntax check
• No behavioral changes for valid JSON responses — guards only activate on malformed input

[teknium1]

Thanks for covering several real malformed-response paths. Four targeted parsers remain unguarded on current main: tools/osv_check.py:165, tools/discord_tool.py:116, tools/browser_cdp_tool.py:237,271, and gateway/platforms/weixin.py:389,413.

Problems

• gateway/platforms/api_server.py:459-471 already has a stronger corrupt-cache implementation: it catches the decode failure, logs it, evicts the poisoned entry, and returns None. The PR's stale hunk should not replace it.
• tools/osv_check.py:46-51 already logs fail-open query failures. Returning [] from the parser would keep the allow behavior but suppress that diagnostic.
• No malformed-response regression tests are included. Existing Discord and Weixin tests cover valid and HTTP-error responses, not invalid successful bodies.

Suggested changes

• Salvage the four still-live guards, omit the ResponseStore hunk, preserve OSV diagnostics, and add targeted malformed-JSON tests for each path.

Automated hermes-sweeper review.

[teknium1]

Current main already handles this more robustly at gateway/platforms/api_server.py:459-471: it logs and deletes the corrupt cache row before returning None. Please omit this stale hunk during salvage so a poisoned entry is not retained.

[teknium1]

check_package_for_malware() currently catches this failure and logs a debug fail-open reason at tools/osv_check.py:46-51. Returning [] here preserves the allow result but loses that diagnostic; log invalid JSON here or propagate a contextual exception instead.