Parser: limit `from SOURCE` to parse-collection/cmp/arith/poss/atom
(stops before parse-logical so `or` is not consumed as binary op),
then collect `or EVENT from SOURCE` pairs via recursive collect-ors!.
Adds :or-sources key to the on-feature parts list.
Compiler: scan-on gains or-sources param (11th); new :or-sources cond
clause extracts the list; terminal `true` branch wraps on-call in
(do on-call (hs-on target event handler) ...) for each extra source.
Test: "can handle an or after a from clause" moved from skip-list to
MANUAL_TEST_BODIES and now passes (1478/1496).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>