fix: self-heal retry rebuilds consumed File objects (no 0-byte re-upload)

send() and send_any() retry with the exact same discord.File objects
after healing a dead webhook, but discord.py closes every File on the
first send's exit - a buffer-backed File's retry then uploads 0 bytes
silently (the buffer sits at EOF and nothing calls reset()), and a
path-backed File raises "I/O operation on closed file" instead.

The healed retry in both methods now routes kwargs through
_rebuild_files_in_kwargs(), which rebuilds a fresh discord.File per
entry in file=/files= from its original source (reopens a path-backed
File, rewinds a still-seekable buffer) before the retry send. A File
that can't be safely rebuilt raises ValueError rather than silently
sending an empty attachment. The first, non-retry send is untouched.

Signed-off-by: disqualifier <dev@disqualifier.me>

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "dpy_webhooks"
-version = "0.1.1"
+version = "0.1.2"
 description = "Per-channel Discord webhook management for discord.py — get-or-create, persist, enforce the cap, send. Config-free, injectable, installable."
 requires-python = ">=3.10"
 dependencies = [