elp(propositions): native-el READ primitive — memory text -> SACRED triples

Phase 3 piece 1. Ports propositions.py off spaCy: the dependency-parser role is
now the el-native parser (parse_spec), and each memory sentence's meaning-spec
IS the triple (subject, predicate, object, modifiers, polarity, tense, source,
confidence). Sentence segmentation + repr parity with propositions.py. NEGATION
SACRED: polarity flows straight from the spec, never dropped/inverted.

Gate (propositions_gate.el): 4/4 SACRED polarity correct on extraction;
multi-sentence memory splits one triple per sentence in reading order with
negation preserved. Built bounded (elc rc=0 peak 24MB, cc rc=0).

Gap (honest): English regular-verb lemmatizer does not restore silent-e
(stores->stor); coreference/passive normalization from the reference not yet
ported (shallow pronoun subject kept as surface).

elp/manifest.el

@@ -81,6 +81,7 @@ build {
         "src/realizer.el",
         "src/semantics.el",
         "src/comprehend.el",
+        "src/propositions.el",
         "src/elp.el",
     ]
 }