fix(jobbank-search): retain all documented repeated filter values (#577)

* fix(jobbank-search): retain all documented repeated filter values

Declare the six array-capable search options repeatable in Bunli metadata. Without it, the CLI parser overwrites earlier occurrences before the handler receives the array, so documented OR filters only search the final value.

Exercise actual search CLI subprocesses through loopback HTTP and assert every RSS and total-count request retains repeated values. Cover all six filters, mixed equals/comma input, and unchanged single-value input; no live portal requests.

* docs(changelog): record fix for #577

CHANGELOG.md

@@ -355,6 +355,8 @@ per-file diff commands.
   a longer number is still caught. Two new `test_verify_pdf.py` cases; the numeric one fails
   on the unbounded pattern.
 
+- **`jobbank-search` preserves repeated filter values** (#577) - repeated documented filter options now retain all supplied values instead of only the last value.
+
 - **`check_framework_version.py`'s git diff read no longer crashes on non-ASCII framework-file
   content** (`tools/check_framework_version.py`) - `run_git()` called
   `subprocess.run(text=True)` without an explicit `encoding`, so output decoded via the host