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).

dist/elp-c-decls.h

@@ -140,8 +140,8 @@ el_val_t build_identity_from_graph(void);
 el_val_t build_np(el_val_t referent, el_val_t slots);
 el_val_t build_pp(el_val_t loc);
 el_val_t build_rules(void);
-el_val_t build_system_prompt(el_val_t ctx);
 el_val_t build_system_prompt(el_val_t ctx, el_val_t chat_mode);
+el_val_t handle_chat_plan(el_val_t body);
 el_val_t build_vocab(void);
 el_val_t build_vp_body(el_val_t slots);
 el_val_t build_vp_from_slots(el_val_t slots);