Make RelatedNode/RelationshipManager generic over peer type (#1063)

[FragmentedPacket]

Fixes #1063. Stacked on top of #763 (base branch is #763's re-sb-20260119-fix-typing-for-protocols-ihs-183); retarget to develop once #763 merges.

Problem

RelatedNode.peer / RelationshipManager are typed against the dynamic InfrahubNode, so traversing a relationship loses the peer's type. Any chain through .peer / .peers collapses to the catch-all Attribute | RelationshipManager | RelatedNode union and fails under mypy/ty with union-attr. This became visible to downstream consumers when py.typed was added in 1.19.0.

Change

• RelatedNode, RelatedNodeSync, RelationshipManager, RelationshipManagerSync are now generic over the peer type (PeerT / PeerTSync), defaulting to InfrahubNode / InfrahubNodeSync (PEP 696) so all existing un-parameterised usage is unchanged.
• infrahubctl protocols parameterises each relationship: device: RelatedNode[NetworkDevice], interfaces: RelationshipManager[NetworkInterface], etc. Core peers are syncified in sync output (tags: RelationshipManagerSync[BuiltinTagSync]); locally generated classes keep their name.
• Generic[...] is a typing-only change — zero runtime cost.

Verification

• SDK: mypy (125 files) ✅, ty ✅, ruff ✅, generator test updated, 252 node/relationship/store unit tests ✅.
• Against a downstream repo (the AI/DC solution) on the released line: relationship traversal union-attr errors went from 52 → 0. (Remaining downstream errors are a separate relationship-assignment issue, bug: assigning to a relationship attribute fails mypy (assignment) for id strings and nodes #1064, plus genuinely-unsound accesses now correctly surfaced, e.g. accessing NetworkInterface-only attributes on a generic NetworkEndpoint peer.)

Notes

• The bundled infrahub_sdk/protocols.py is left as-is (bare relationships still resolve via the InfrahubNode default); it can be regenerated with the new generator separately.

🤖 Generated with Claude Code

---

Summary by cubic

Make RelatedNode/RelatedNodeSync and RelationshipManager/RelationshipManagerSync generic over their peer type so .peer, .peers, and indexing preserve the peer's concrete type. Also update infrahubctl protocols to emit parameterized relationships; existing code stays compatible via InfrahubNode/InfrahubNodeSync defaults, fixing #1063.

• New Features
  • Defaults use PEP 696 to InfrahubNode/InfrahubNodeSync, so un-parameterized usage continues to work.
  • Protocol generator now outputs RelatedNode[Peer] and RelationshipManager[Peer]; sync output references PeerSync when available.

^{Written for commit 49bd3ed. Summary will update on new commits.}

[codecov]

Codecov Report

❌ Patch coverage is 93.93939% with 2 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
infrahub_sdk/node/related_node.py	87.50%	2 Missing ⚠️

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Flag	BASE (6c5bd98)	HEAD (49bd3ed)
integration-tests	1	0

@@                                 Coverage Diff                                 @@
##           re-sb-20260119-fix-typing-for-protocols-ihs-183    #1065      +/-   ##
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- Coverage                                            80.38%   72.38%   -8.01%     
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  Files                                                  115      115              
  Lines                                                 9894     9899       +5     
  Branches                                              1517     1518       +1     
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- Hits                                                  7953     7165     -788     
- Misses                                                1418     2228     +810     
+ Partials                                               523      506      -17     

Flag	Coverage Δ
integration-tests	?
python-3.10	51.40% <42.42%> (-0.01%)	⬇️
python-3.11	51.40% <42.42%> (-0.03%)	⬇️
python-3.12	51.42% <42.42%> (+0.01%)	⬆️
python-3.13	51.40% <42.42%> (-0.01%)	⬇️
python-3.14	53.07% <42.42%> (+0.01%)	⬆️
python-filler-3.12	24.06% <51.51%> (+0.01%)	⬆️

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Files with missing lines	Coverage Δ
infrahub_sdk/node/relationship.py	70.87% <100.00%> (-8.80%)	⬇️
infrahub_sdk/protocols_generator/generator.py	95.12% <100.00%> (+0.12%)	⬆️
infrahub_sdk/node/related_node.py	84.57% <87.50%> (-7.88%)	⬇️

... and 30 files with indirect coverage changes

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[cubic-dev-ai]

No issues found across 6 files

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