feat: port arbor, dharma, forge El source into monorepo

Brings the remaining foundation repos that were not included in the
original monorepo consolidation:

- arbor/vessels/ — 6 vessels (arbor-cli, arbor-core, arbor-diagram,
  arbor-layout, arbor-parse, arbor-render) with manifests + src/main.el
- dharma/ — CGI Provenance Registry package (flat layout, 14 .el files
  across registry/, sandbox/, training/, validation/, tests/)
- forge/ — consciousness channel tool (8 src .el files + new manifest.el)
- elp/src/ — 36 test fixture files not carried over in original merge
  (dedup_*, realizer_*, semantics_*, morph_*, ext_*, one_extern_* helpers)

el-ide, engram, elql are already complete in ide/, engram/, ql/.

dharma/tests/internal_state/test_body_contains_key.el

@@ -0,0 +1,56 @@
+// test_body_contains_key.el — verifies body_contains_key correctly
+// distinguishes "user asserted this field" from "user did not mention it".
+// This is the gate the PATCH endpoint uses to enforce immutability.
+
+fn body_contains_key(body: String, key: String) -> Bool {
+    return str_contains(body, "\"" + key + "\":")
+}
+
+fn assert_true(name: String, got: Bool) -> Bool {
+    if got {
+        println("PASS " + name)
+        return true
+    }
+    println("FAIL " + name + " want=true got=false")
+    return false
+}
+
+fn assert_false(name: String, got: Bool) -> Bool {
+    if got {
+        println("FAIL " + name + " want=false got=true")
+        return false
+    }
+    println("PASS " + name)
+    return true
+}
+
+fn main() -> Void {
+    let b1: String = "{\"post_reasoning\":\"x\"}"
+    assert_true("present-non-empty", body_contains_key(b1, "post_reasoning"))
+
+    // Empty value still counts as "asserted" — user mentioned the key.
+    let b2: String = "{\"post_reasoning\":\"\"}"
+    assert_true("present-empty-string", body_contains_key(b2, "post_reasoning"))
+
+    // Key absent.
+    let b3: String = "{\"gap_summary\":\"x\"}"
+    assert_false("absent", body_contains_key(b3, "post_reasoning"))
+
+    // Substring of another key must NOT match.
+    // E.g. "tags":  vs "tag":  — distinct.
+    let b4: String = "{\"tags\":\"a,b,c\"}"
+    assert_false("substring-distinct", body_contains_key(b4, "tag"))
+    assert_true("exact-tags", body_contains_key(b4, "tags"))
+
+    // Immutable-field detection: PATCH must reject these.
+    let b5: String = "{\"pre_reasoning\":\"new value\",\"post_reasoning\":\"x\"}"
+    assert_true("detect-pre_reasoning", body_contains_key(b5, "pre_reasoning"))
+    assert_true("detect-post_reasoning", body_contains_key(b5, "post_reasoning"))
+
+    let b6: String = "{\"cgi_id\":\"x\"}"
+    assert_true("detect-cgi_id", body_contains_key(b6, "cgi_id"))
+
+    // No false-positive if the value happens to contain the same string.
+    let b7: String = "{\"trigger\":\"contained pre_reasoning string\"}"
+    assert_false("no-false-positive-from-value", body_contains_key(b7, "pre_reasoning"))
+}