feat(@convex-dev/better-auth): migrate to better-auth 1.6 (pr323)

[ramonclaudio]

Add bun/npm/pnpm patches for @convex-dev/better-auth@0.11.4 that bring in the better-auth 1.6 migration from upstream PR get-convex/better-auth#323.

The patch bumps the peer range to >=1.6.0 <1.7.0, accepts the new Where.mode field in adapter validators (so api.adapter.findOne stops throwing ArgumentValidationError), passes asResponse: false at 7 internal plugin endpoint call sites (6 in convex, 1 in cross-domain) so 1.6's flipped shouldReturnResponse default doesn't turn { token } into undefined (JWT cookies becoming the literal string "undefined") or crash setSessionCookie on cross-domain, and silences the oidcProvider deprecation warning with __skipDeprecationWarning.

Built by diffing the @convex-dev/better-auth@0.11.4 npm tarball against a clean tsc build of the PR tip at e17d80e. Excludes test files, example lockfiles, and CHANGELOG.md. package.json version field left at 0.11.4 (not bumped to 0.12.0) so the installed tag matches what tooling reads; only the better-auth peer range is changed there. Verified with patch -p1 --dry-run against a fresh npm pack @convex-dev/better-auth@0.11.4 for all three variants, zero rejected hunks.

• add bun patch at packages/@convex-dev/better-auth/bun/@convex-dev%2Fbetter-auth@0.11.4-pr323.patch (paths relative to package root)
• add npm (patch-package) patch at packages/@convex-dev/better-auth/npm/@convex-dev+better-auth+0.11.4-pr323.patch (paths prefixed with node_modules/@convex-dev/better-auth/)
• add pnpm patch at packages/@convex-dev/better-auth/pnpm/@convex-dev__better-auth@0.11.4-pr323.patch (paths relative to package root)
• add row to README.md ## Open table linking the three patches and the upstream PR

Consumers applying this patch must also bump better-auth in their app to ^1.6.0 so the new peer range resolves.