fix(classifier-match): allow same-direction delegation bus access connections (AADL v2.3 §9.4)

[avrabe]

Reproducer

package Repro
public
  with Buses;

  device InnerDevice
  features
    eth : provides bus access Buses::Ethernet;
  end InnerDevice;

  system Outer
  features
    eth_ext : provides bus access Buses::Ethernet;
  end Outer;

  system implementation Outer.impl
    subcomponents
      inner : device InnerDevice;
    connections
      -- Delegation: both 'provides' — valid per AADL v2.3 §9.4
      c_eth : bus access eth_ext <-> inner.eth;
  end Outer.impl;
end Repro;

Expected: no error. Actual on v0.9.3: classifier_match: connection 'c_eth': both source 'eth_ext' and destination 'eth' are 'provides' — access connections require provides ↔ requires pairing. User reports 32 occurrences in their real OEM SIP-internal wiring model on x86_64-linux.

Summary

• Bug: spar applied the peer-connection rule (provides ↔ requires) uniformly to every access connection, falsely flagging valid delegation connections where both ends are provides (or both requires).
• Root cause: check_access_match in classifier_match.rs didn't distinguish peer from delegation; it only checked src_ak == dst_ak.
• Fix: detect delegation as "exactly one endpoint's ConnectionEnd.subcomponent is None" (i.e. that end references the enclosing component's own feature, not a subcomponent's). For delegation, directions must MATCH; for peer, they must oppose. Existing peer-error wording is preserved verbatim (golden-test stable); delegation mismatches use fresh wording.
• Spec: AADL v2.3 / AS5506D §9.4. Same rule applies to data-access and subprogram-access connections, which share the code path and benefit uniformly.

Test plan

• bus_access_delegation_both_provides_ok — exact user MWE; no diagnostic.
• bus_access_delegation_both_requires_ok — same shape, both requires; no diagnostic.
• bus_access_peer_provides_to_requires_ok — peer regression (Provides ↔ Requires) still clean.
• bus_access_peer_both_provides_errors — peer regression: both-provides still errors with original wording.
• bus_access_peer_both_requires_errors — peer regression: both-requires still errors with original wording.
• bus_access_delegation_directions_mismatch_errors — delegation provides/requires mismatch errors with new wording.

All 38 classifier_match tests pass; cargo clippy --workspace --all-targets -- -D warnings clean; cargo fmt clean.

🤖 Generated with Claude Code

[codecov]

Codecov Report

❌ Patch coverage is 99.59677% with 1 line in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
crates/spar-analysis/src/classifier_match.rs	99.59%	1 Missing ⚠️

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