Third Phase 2 site migration. Default filename in the dialog now
comes from rendering the library_filename_template against the post,
so users see their templated name and can edit if they want. Drops
the legacy hardcoded "post_" prefix on the default — anyone who wants
the prefix can put it in the template.
The actual save still routes through save_post_file with
explicit_name set to whatever the user typed, so collision resolution
runs even on user-chosen filenames (sequential _1/_2 if the picked
name already belongs to a different post in the library).
behavior change from v0.2.3: Save As into saved_dir() now registers
library_meta. Previously Save As never wrote meta regardless of
destination. If a file is in the library it should be searchable —
this fixes that.
pax
b7cb021d1b