fix(ci): allow out-of-repo paths through the agent hook pre-check (#1993)

* fix(ci): allow out-of-repo paths through the agent hook pre-check

The pre hook treated every path that normalizes outside the repository
as "cannot determine edited paths" and blocked the tool call with exit
2. That blocked agent writes to user settings and session scratchpad
files - paths that cannot be the generated file this guard protects.

A payload with extractable paths that all resolve outside the repo now
passes; only a payload with no extractable path at all is refused.

* fix(ci): refuse empty path candidates in the agent hook pre-check

An empty or whitespace file_path made rawPaths non-empty while every
candidate normalized to null, so the out-of-repo allowance would have
passed a payload with no usable path. Only a candidate that is
non-empty after trimming counts as an outside-repo path; anything else
still fails closed.

* fix(ci): trim path candidates again after quote stripping

A candidate whose content is whitespace inside quotes survived the
outside-path predicate, which trims before stripping quotes but not
after. Re-trim so only a candidate with real content counts as an
outside-repo path.

* style(ci): apply Biome formatting to the agent hook