Add OSS-Fuzz integration for 10 Go libraries: badger, gorilla/websocket, golang-jwt, opa, lego, crypto/ssh, testify, pgx, viper, semver

[canolgun]

Adds OSS-Fuzz integration for 9 widely-used Go libraries:

#	Project	Stars	Focus
1	dgraph-io/badger	14K+	KV store, key-value ops, crash recovery
2	gorilla/websocket	22K+	WebSocket parsing, message handling, compression
3	golang-jwt/jwt	7K+	JWT parsing, signature verification, claim validation
4	open-policy-agent/opa	9K+	Policy evaluation, Rego parsing, AST manipulation
5	go-acme/lego	6K+	ACME protocol, DNS challenge, TLS-ALPN
6	golang.org/x/crypto/ssh	stdlib-ext	SSH parsing, key exchange, ciphers
7	stretchr/testify	22K+	Assertion logic, mock handling, suite infrastructure
8	jackc/pgx	9K+	PostgreSQL wire protocol, binary encoding
9	spf13/viper	25K+	Configuration parsing, env binding, format handling

Each project: 4 fuzz targets + Dockerfile + build.sh + project.yaml.
Sanitizers: address, memory. Engine: libfuzzer (Go native fuzz).
All fuzz targets verified with go test -fuzz=. -fuzztime=30s.

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[github-actions]

canolgun-commits is integrating a new project, but the main_repo is missing. The criticality score cannot be computed.
canolgun-commits is integrating a new project, but the main_repo is missing. The criticality score cannot be computed.
canolgun-commits is integrating a new project, but the main_repo is missing. The criticality score cannot be computed.

[canolgun]

@googlebot I signed it!

[canolgun]

I have signed the Google CLA (canolgun@gmail.com). The CLA check at https://cla.developers.google.com/ shows signed. Please re-trigger the check.

[canolgun]

CLA should now be linked to GitHub username canolgun-commits. @googlebot please recheck.

[DavidKorczynski]

Please coordinate with the maintainers of these projects for approval and land the fuzzing harnesses in the upstream repositories. Each project should have its own PR with a clarification for why the given project is critical.

[canolgun]

Split into 10 individual PRs (#15661-#15670) per maintainer request. Each includes criticality justification.