Fix: handle both recipe path and json body requests

[rugeli]

Problem

in feature/server-passed-recipe-json, we replaced uuid.uuid4() with dedup_hash as the job id. when a recipe path is sent, body is none, causing issues in generating dedup_hash

Solution

• use dedup_hash as job_id only for body requests, fall back to uuid for recipe path requests

###behaviors:

1. recipe path request:

• job_id = uuid, no dedup
• matches the behavior on main
• return {"jobId": "uuid string"}

2. json body request:

• job_id = dedup_hash
• dedup check via job_exists() before packing
• if body is new --> pack
• return {"jobId": "sha hash..."}

Type of change

• Bug fix (non-breaking change which fixes an issue)

[rugeli]

only key lines

[github-actions]

Packing analysis report

Analysis for packing results located at cellpack/tests/outputs/test_spheres/spheresSST

Ingredient name	Encapsulating radius	Average number packed
ext_A	25	236.0

Packing image

Distance analysis

Expected minimum distance: 50.00
Actual minimum distance: 50.01

Ingredient key	Pairwise distance distribution
ext_A