fix(resources): accept bare object/array responses on create/update paths

[asachs01]

Summary

Fixes the systemic write-path crash reported in wyre-technology/halopsa-mcp#76: every create()/update() (plus agents.me(), tickets.addAction(), tickets.addAttachment()) read the response envelope unguarded (response.<key>[0]), so when HaloPSA returns the created entity bare instead of enveloped, the SDK throws TypeError: Cannot read properties of undefined (reading '0') — after the 2xx write landed. Callers that retried on the error duplicated records in production.

• Extend unwrapSingle to handle all three response shapes HaloPSA emits: enveloped ({ actions: [{...}] }), bare object ({ id: 1, ... }), and bare array ([{ id: 1, ... }]). The bare-array case previously fell through to return response as T, silently handing back an array typed as a single entity.
• Route all 41 unguarded sites across 17 resource files through unwrapSingle, matching the idiom the get() paths already use. The per-site Failed to create/update <entity> throws are now actually reachable when no entity comes back.

Test plan

• New tests/unit/resources.test.ts: table-driven over all 41 sites × 4 shapes (enveloped, bare object, bare array, empty envelope → throw). The bare-object and bare-array cases fail on main (84 failures) and pass with this change.
• unwrapSingle unit tests extended with bare-array and empty-bare-array cases.
• npm run build, npm test (260/260), and npm run lint all green.

Refs wyre-technology/halopsa-mcp#76

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