refactor(calibredb-epub): reorder defuns above their use-package consumers

`make compile' had been flagging `cj/calibredb-clear-filters' and
`cj/nov-jump-to-calibredb' as "defined multiple times in this file"
since 2026-05-12.  Investigation: there's only one `(defun ...)' of
each in the source -- use-package's `:bind' expansion makes the
byte-compiler count the referenced symbol as a definition when the
function is defined in the same file, then it sees the real
`defun' later and warns about a redefinition.

Reorder so each `defun' appears before the `use-package' that
references it via `:bind':

- `cj/calibredb-clear-filters' moved above (use-package calibredb).
- `cj/nov--metadata-get', `cj/nov--file-path', and
  `cj/nov-jump-to-calibredb' moved above (use-package nov).  The
  two helpers had to move with the public function so the
  byte-compiler doesn't emit fresh free-function warnings.

Source content unchanged; only line positions move.  Both
duplicate-definition warnings are gone after this; full unit suite
still green.

0 files changed, 0 insertions, 0 deletions