fix(build): close real local-build gaps found in a hands-on build/run audit

Three verified, currently-live problems, each closed with real evidence
(full trace kept in Neuron memory, tags neuron-technologies/neuron,build-audit):

1. dist/soul.c was stale relative to main's own chat.el (11 commits / 459
   lines behind, missing PR #122's OpenAI-tools + agentic-loop work and its
   two "silently break chat" fixes). tools/soulc-stamp.sh --check confirmed
   it; tools/build-soul-from-dist.sh correctly refused to build (exit 9).
   Regenerated and re-stamped. No runnable regen script existed anywhere
   upstream — added tools/regenerate-soul-amalgam.sh, which reproduces the
   committed amalgam's exact symbol set (byte-for-byte content match, modulo
   the genuinely new PR #122 functions) and is documented end-to-end in
   AGENTS.md, including three real elc/elb toolchain gotchas found and
   root-caused along the way (stale .elh caches silently truncating builds;
   elb cannot produce this repo's single-TU amalgam; elc silently drops the
   first function(s) after a comment block in a flat-concatenated compile).

2. tools/build-soul-from-dist.sh failed to link on macOS (`ld: library 'ssl'
   not found` — Homebrew's openssl@3 is keg-only) and was missing -lssl
   -lcrypto entirely, drifted from CI's own working recipe. Fixed: adds
   -L$(brew --prefix openssl@3)/lib on Darwin, matches CI's link line.
   Verified: dist/neuron now builds and boots clean on a throwaway
   port/HOME (never touched the live :7770/:8742).

3. Untracked committed *.elh compiler-header caches (elc/elb prefer a stale
   cached header over recompiling its source, silently, with no error —
   this is what caused an under-resolved 251-2541-function amalgam multiple
   times during this audit before the cause was found). Removed from git,
   gitignored going forward.

Also: AGENTS.md and README.md existed on disk but were never committed
(git log on both returned nothing) and documented the pre-collapse ~90-tool
MCP surface as current. Committed corrected versions reflecting the live
9-op surface (read/write/relate/supersede/think/attend/assert/ground/learn,
merged in #153) and the audit-verified build recipe/port topology.

Added connectd/ — a minimal local-dev stub for the neuron-connectd MCP
sidecar. routes.el/chat.el call 127.0.0.1:7771 for it right now on every
soul boot and agentic turn per a real, detailed 2026-06-13 spec
(mcp-connectors-adoption-spec.md); the sidecar itself was never built.
Meanwhile :7771 is a live three-way collision (axon's unbuilt-Rust default,
this connectd contract, and council — the anti-confabulation service
actually running there in prod, which live-answers both other things'
requests with unrelated 404s instead of a clean bridge-down signal). This
stub only implements the documented contract as "zero connectors
configured" for local-dev correctness; it does not attempt OAuth or a real
MCP client — that is a real, separate product decision. See
connectd/README.md for the full trace and the open question left for Will.

connectd/connectd_service.py

@@ -0,0 +1,115 @@
+#!/usr/bin/env python3
+"""
+neuron-connectd — MCP connector bridge (LOCAL-DEV STUB).
+
+THIS IS NOT THE FULL SIDECAR. The full design lives in
+neuron-technologies/docs/research/mcp-connectors-adoption-spec.md (2026-06-13,
+"Status: Draft for build"): a TypeScript/Python sidecar using the official MCP
+SDK that spawns real MCP servers (stdio or streamable-HTTP/SSE), does OAuth,
+and namespaces their tools as mcp__<serverId>__<toolName>. That sidecar was
+never built (build-audit, 2026-08-15: no neuron-connectd source existed
+anywhere on disk before this file).
+
+WHY THIS STUB EXISTS: routes.el (handle_connectors, connectd_get/connectd_post)
+and chat.el (connector_tools_json, dispatch_tool's mcp__* routing,
+tool_auto_approved) were built to the spec and hardcoded to 127.0.0.1:7771 —
+they are LIVE and calling that port right now on every soul boot and every
+agentic turn. With nothing real listening there, three unrelated services
+collide on :7771 (see connectd/README.md): council (which IS what's bound
+there in Will's live environment today) silently answers with unrelated
+404 JSON, which is worse than a clean "connection refused" bridge-down
+response, because it can be misparsed as a real (if empty) reply instead of
+the "bridge unreachable" path the soul code already handles gracefully.
+
+This stub implements ONLY the documented HTTP contract, with zero connectors
+ever configured: empty tool list, empty server list, "not configured" on any
+mutating call. It gives a fresh local soul the CORRECT graceful-degradation
+behavior the soul code already expects for "no connectors set up yet" — not
+the wrong-shaped 404 noise a port collision produces. It does not spawn any
+MCP server, does no OAuth, and reads no ~/.neuron/connectors.json (there is
+nothing to read yet). Building the real sidecar is a separate, larger,
+Will-decision-needed product task — see README.md.
+
+Usage:
+    python3 connectd_service.py [--port 7771]
+"""
+
+import argparse
+
+import uvicorn
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+from pydantic import BaseModel
+
+app = FastAPI(title="neuron-connectd (local-dev stub)")
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+
+class ToolCall(BaseModel):
+    name: str
+    input: dict = {}
+
+
+@app.get("/healthz")
+def healthz():
+    return {"status": "ok", "stub": True}
+
+
+@app.get("/mcp/tools")
+def mcp_tools():
+    # Matches the spec's contract shape exactly (section 4, "HTTP contract").
+    # Empty because zero connectors are configured — this is the correct,
+    # intended-by-design empty state, not a failure.
+    return {"tools": []}
+
+
+@app.post("/mcp/call")
+def mcp_call(body: ToolCall):
+    return {"ok": False, "error": "no connectors configured (neuron-connectd stub)"}
+
+
+@app.get("/mcp/servers")
+def mcp_servers():
+    return {"servers": []}
+
+
+@app.post("/mcp/servers/add")
+def mcp_servers_add():
+    return {"ok": False, "error": "neuron-connectd stub does not implement connector management yet"}
+
+
+@app.post("/mcp/servers/toggle")
+def mcp_servers_toggle():
+    return {"ok": False, "error": "neuron-connectd stub does not implement connector management yet"}
+
+
+@app.post("/mcp/servers/auto-approve")
+def mcp_servers_auto_approve():
+    return {"ok": False, "error": "neuron-connectd stub does not implement connector management yet"}
+
+
+@app.post("/mcp/servers/remove")
+def mcp_servers_remove():
+    return {"ok": False, "error": "neuron-connectd stub does not implement connector management yet"}
+
+
+@app.post("/mcp/servers/secret")
+def mcp_servers_secret():
+    return {"ok": False, "error": "neuron-connectd stub does not implement connector management yet"}
+
+
+@app.post("/mcp/oauth/start")
+def mcp_oauth_start():
+    return {"ok": False, "error": "oauth not implemented in the neuron-connectd stub"}
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+    parser.add_argument("--port", type=int, default=7771)
+    args = parser.parse_args()
+    uvicorn.run(app, host="127.0.0.1", port=args.port, log_level="info")