Harden crypto callback, ASN.1 parsing, param-enc and marshalling; add negative tests

[aidangarske]

F-6839, F-6840, F-6841, F-6842, F-6843, F-6844, F-6845, F-6846, F-6847, F-6848, F-6849, F-6850

[Copilot]

Pull request overview

This PR hardens several security-sensitive paths in wolfTPM around parameter encryption hashing, TPM public-area marshalling, ASN.1 parsing, and the wolfCrypt crypto callback, and adds unit tests intended to lock in the new boundary/error handling.

Changes:

• Add new unit tests for param-encryption boundary conditions, response HMAC verification, ASN.1 error handling, crypto callback edge cases, and public marshal/parse round-trips.
• Scrub hash context stack state after cpHash/rpHash computation.
• Clamp several TPM2B_* size fields during public-area marshalling and add an ECC verify guard against oversized DER R/S causing offset underflow.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
tests/unit_tests.c	Adds new negative/boundary tests across param-enc, ResponseProcess HMAC, public marshalling, CryptoDevCb, and ASN.1 parsing.
src/tpm2_param_enc.c	Adds explicit stack zeroization of hash contexts after cpHash/rpHash calculation.
src/tpm2_packet.c	Clamps public-area authPolicy and several unique.* sizes before appending to packet.
src/tpm2_cryptocb.c	Rejects ECDSA verify signatures with R/S larger than key size to prevent pad-offset underflow.
src/tpm2_asn.c	Normalizes ASN header decode success return to 0 and updates callers accordingly.
src/fwtpm/fwtpm_crypto.c	Adds clarifying comments about ML-KEM secret length per FIPS 203 errata.