Accept adapter-lowered target obstruction coordinates

[flyingrobots]

The generic executable-operation lowerer and verifier must validate compiler-produced Target IR against the adapter's target obstruction coordinate, not the source-lawpack failure name.

Acceptance:

• lowerer and verifier accept the declared generic target obstruction coordinate;
• source failure-to-target obstruction mapping remains independently corroborated through the lawpack adapter;
• focused provider tests and the external Hello Echo build pass;
• production modules remain application-neutral.

Blocks flyingrobots/edict#169.

[coderabbitai]

🔗 Related PRs

#672 - Implement Echo Edict provider lowerer [merged]
#673 - Implement the Echo Target IR semantic verifier [merged]
#675 - Generate Target-IR-bound Echo provider helpers [merged]
#677 - Prove Edict provider conformance and semantic parity [merged]

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