manage_memory descriptions: explicit deferral to manage_contact for person info

Even with manage_contact in the retrieved tool set, models were still
defaulting to manage_memory when the user pasted an address + 'save for
<person>'. Both tools were in front of the model and it picked memory.

Tighten both descriptions to steer at decision-time:
- agent_loop.py manage_memory description: clarify scope is facts
  about the USER, with an explicit 'DO NOT use for info about another
  person' + a 'use manage_contact instead' line.
- tool_index.py manage_memory description: same in shorter form, so the
  embedded retrieval signal is consistent with the prompt-time
  description.

src/agent_loop.py

@@ -396,7 +396,7 @@ Generate an image. Line 1 = description, line 2 = model name, line 3 = WxH (e.g.
     "ask_teacher": "- ```ask_teacher``` — Escalate a hard question to a more capable model. Line 1 = model name or 'auto', rest = the question. Use when stuck or need expert knowledge.",
     "list_models": "- ```list_models``` — Show all available AI models across all endpoints. Use when user asks what models are available.",
     "manage_session": "- ```manage_session``` — Rename, archive, delete, fork, switch, or `list` chats (the UI calls them 'chats'; 'session' is internal). Line 1 = action (list/switch/rename/archive/unarchive/delete/important/unimportant/truncate/fork), Line 2 = exact chat id from `list_sessions` (or `current` where supported). For delete/archive/truncate, always list first and reuse the exact id; never invent placeholder ids. `switch`/`open` returns a clickable anchor link the user can tap to open the chat — use for \"open my X chat\".",
-    "manage_memory": "- ```manage_memory``` — Manage the user's persistent memory (facts, identity, preferences, context that persists across chats). Line 1 = action (list/add/edit/delete/search), rest = content. Use when user says 'remember this', states identity facts like 'my name is <name>' / 'call me <name>' / 'I live in <place>', or asks about stored memories.",
+    "manage_memory": "- ```manage_memory``` — Manage the user's persistent memory (facts about the USER themselves, their preferences, context that persists across chats). Line 1 = action (list/add/edit/delete/search), rest = content. Use when user says 'remember this' about themselves, states identity facts like 'my name is <name>' / 'call me <name>' / 'I live in <place>', or asks about stored memories. DO NOT use for info about another person (their address, phone, email, birthday) — that goes in `manage_contact`. If the user pastes an address/phone with a name and says 'save this for <person>', use `manage_contact add` with the address arg, NOT manage_memory.",
     "manage_skills": "- ```manage_skills``` — Skill registry (SKILL.md format). Args (JSON): {\"action\": \"list|view|view_ref|search|add|edit|patch|publish|delete\", ...}. `list` returns the index of available skills (published + teacher-escalation drafts); `view name=foo` fetches the full SKILL.md; `view_ref name=foo path=...` loads a reference file under the skill directory. For `add`, provide an explicit kebab-case `name` and only report the exact returned name, because storage may normalize or dedupe it. Use this BEFORE doing domain work — there may already be a procedure (published or draft) that prescribes the correct steps. Drafts written by the teacher loop are authoritative guidance even though they're not yet published.",
     "manage_tasks": "- ```manage_tasks``` — Create and manage scheduled background tasks (recurring AI jobs). Args (JSON): {\"action\": \"list|create|edit|delete|pause|resume|run\", ...}",
     "manage_endpoints": "- ```manage_endpoints``` — Add, remove, or configure AI model API endpoints. Args (JSON): {\"action\": \"list|add|delete|enable|disable\", ...}. Use when user wants to add a new AI provider.",