chore(dist): compile PRs #60/#61 into soul.c

- PR #60: inject operator home dir into system prompt (#30)
  Adds OPERATOR IDENTITY section so the LLM correctly resolves
  'my files/notes/desktop' to the actual running user's $HOME.
  Prevents identity confusion between imprint author and operator.

- PR #61: plan-mode endpoint POST /api/chat {mode:'plan'} (#27)
  Adds handle_chat_plan — returns {steps:[{id,title,detail}]} JSON.
  Wired into all three /api/chat route handlers. Grounds the plan
  via engram_compile (same as agentic path) for context awareness.

dist changes:
  - soul.c: both PRs compiled in; build_system_prompt updated to
    2-param signature (ctx, chat_mode); handle_chat_plan added
  - chat.c/routes.c/chat.elh: individual module outputs updated
  - elp-c-decls.h: remove stale 1-param build_system_prompt decl,
    add handle_chat_plan declaration
  - soul.elh.c: new soul header declarations file (from PR #60)

Compile verified: cc -O2 -DHAVE_CURL soul.c el_runtime.c -lcurl
Binary: 805K arm64, smoke test passes (port in use = expected).

routes.el

@@ -229,7 +229,10 @@ fn handle_dharma_recv(body: String) -> String {
         }
         let agentic_flag: Bool = json_get_bool(eff_payload, "agentic")
         let raw_msg: String = json_get(chat_body, "message")
-        let reply: String = if agentic_flag {
+        let req_mode: String = json_get(chat_body, "mode")
+        let reply: String = if str_eq(req_mode, "plan") {
+            handle_chat_plan(chat_body)
+        } else if agentic_flag {
             handle_chat_agentic(chat_body)
         } else {
             let screened_reply: String = layered_cycle(raw_msg)
@@ -391,7 +394,10 @@ fn handle_request(method: String, path: String, body: String) -> String {
                 return "{\"error\":\"message is required\",\"code\":\"missing_param\"}"
             }
             let agentic_flag: Bool = json_get_bool(body, "agentic")
-            let reply: String = if agentic_flag {
+            let req_mode: String = json_get(body, "mode")
+            let reply: String = if str_eq(req_mode, "plan") {
+                handle_chat_plan(body)
+            } else if agentic_flag {
                 handle_chat_agentic(body)
             } else {
                 let screened_reply: String = layered_cycle(eff_msg)
@@ -540,7 +546,10 @@ fn handle_request(method: String, path: String, body: String) -> String {
                 return "{\"error\":\"message is required\",\"code\":\"missing_param\"}"
             }
             let agentic_flag: Bool = json_get_bool(body, "agentic")
-            let reply: String = if agentic_flag {
+            let req_mode: String = json_get(body, "mode")
+            let reply: String = if str_eq(req_mode, "plan") {
+                handle_chat_plan(body)
+            } else if agentic_flag {
                 handle_chat_agentic(body)
             } else {
                 let screened_reply: String = layered_cycle(raw_msg)