Swift method names should start with lowercase (extract, extractText, etc.).
The lc_first filter was already registered in the code generator but not
applied to method declarations. This fixes the template to use lowercase
method names matching Swift conventions.
Verification:
- All 9 contract methods generate with correct naming
- All 8 error cases generate correctly
- Package.swift specifies macOS 13+ and Linux support
- README documents iOS as unsupported
- Argo workflow synced to declarative-config
Closes pdftract-5lvpu
Verification note: notes/pdftract-5lvpu.md
cbaec52c20