### Issues:

Addresses the need to convert third-party test vectors to AWS-LC's
file_test.h format and track which vectors are tested. Currently, test
vectors are manually converted and there's no systematic way to verify
that all vectors in `third_party/` are actually used in tests.

### Description of changes:

Extends the test vector infrastructure from #2811 with two new phases
(each can be skipped independently):

- **Convert**: Transforms Wycheproof JSON test vectors to file_test.h
format via `convert_vector.py` (inspired by the existing Go converter)
- **Spec**: Generates `vectors_spec.md` with MUST requirements and uses
duvet to verify that test files contain corresponding annotations

Converts and integrates `aes_gcm_test` from the latest upstream
Wycheproof as a proof of concept, the test and duvet verification pass.

### Call-outs:

- Conversion is Python-based (not Go) to keep tooling unified within the
vectors system
- The existing Go converter at `util/convert_wycheproof/` will be
removed once all test vectors are migrated to the new system
- Also removes now-outdated `aes_gcm_test` vector in
`third_party/wycheproof_testvectors/`
- Duvet verifies annotation presence but doesn't verify test coverage

### Testing:

- Unit tests in `convert_vector.py` verify JSON to file_test.h
conversion
- Tested full sync workflow and various skip flag combinations
- Verified error handling (invalid sources, missing files)
- Confirmed duvet correctly tracks annotation in
`crypto/cipher_extra/aead_test.cc`

Run the full workflow with `cd third_party/vectors && ./sync.py`.

Run the migrated test with `cd build && ./crypto/crypto_test
--gtest_filter="AEADTest.WycheproofAESGCM"`

By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 license and the ISC license.

…2887)

### Issues:

Migrating Wycheproof test vectors to the new `third_party/vectors/`
system introduced in #2811 and extended in #2839, enabling systematic
tracking and traceability.

### Description of changes: 

Migrates 30 test vector files to the new vector system:
- 10 ECDSA test files (secp224r1, secp256r1, secp384r1, secp521r1,
secp256k1 with SHA-224, SHA-256, SHA-384, SHA-512)
- 4 DSA test files (2048-bit and 3072-bit keys with SHA-224, SHA-256)
- 1 EdDSA test file (Ed25519)
- 12 RSA PKCS#1 signature verification test files (2048, 3072, 4096,
8192-bit keys with SHA-224, SHA-256, SHA-384, SHA-512)
- 5 RSA PKCS#1 signature generation test files (1024, 1536, 2048, 3072,
4096-bit keys including weak key sizes)
- 3 RSA PKCS#1 v1.5 decryption test files (2048, 3072, 4096-bit keys)

Each migration adds upstream JSON vectors and converted txt files to
`third_party/vectors/`, updates test files with new paths and duvet
annotations for traceability, and removes old files from
`third_party/wycheproof_testvectors/`.

### Call-outs:

- Previous `rsa_signature_test.txt` superseded by
`rsa_signature_*_sha*_test.txt` files with explicit key sizes
- Previous `rsa_sig_gen_misc_test.txt` superseded by
`rsa_pkcs1_*_sig_gen_test.txt` files with explicit key sizes
- Remaining test vectors will be migrated in follow-up PRs

### Testing:

All migrated tests pass and duvet verification succeeds:
```bash
cd build && ./crypto/crypto_test
cd third_party/vectors && python3 sync.py
```

By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 license and the ISC license.