fix(plugin): justify the one shellcheck finding (SC1007, false positive)

First CI run with shellcheck (run 3029) flagged exactly one thing:

  scribe_session_context.sh:44
  SC1007 Remove space after = if trying to assign a value
  here=$(CDPATH= cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)

`CDPATH= cd` is the deliberate POSIX idiom for running a single command
with CDPATH empty — it stops `cd` resolving through the operator's CDPATH
and echoing the resolved path into our stdout, which for a hook whose
stdout IS its protocol would be a real bug. shellcheck cannot distinguish
that from a typo'd `CDPATH=cd`, so this is a false positive.

Scoped `# shellcheck disable=SC1007` with the reason above it, matching
how CI-runner's own scripts/install-common.sh handles SC2086. One
line-scoped disable, no file-level or blanket suppression — a lint you
silence broadly stops being a lint.

Everything else in that run passed, including the parts that could only
run once jq was installed: all four hooks exit 0 and stay silent
unconfigured and against a refused connection, with the session-context
hook correctly still emitting its static floor.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UaYUaouG9jjhATyuxCKrQs

plugin/hooks/scribe_session_context.sh

@@ -41,6 +41,11 @@ set -uo pipefail
 
 command -v jq >/dev/null 2>&1 || exit 0   # needed to emit the JSON envelope safely
 
+# `CDPATH= cd` is deliberate, not a typo'd assignment: it runs this one `cd`
+# with CDPATH empty, so an operator whose CDPATH happens to contain a matching
+# directory name can't send us somewhere else — and `cd` won't echo the resolved
+# path into our output. shellcheck can't tell that idiom from `CDPATH=cd`.
+# shellcheck disable=SC1007
 here=$(CDPATH= cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd) || exit 0
 
 # SessionStart delivers a JSON event on stdin; `source` is startup|resume|compact|clear.