docs(cli): add Agent Mode + mem0 identify to /platform/cli

PR #5123 added Agent Mode to the CLI but only updated docs/changelog/sdk.mdx;
the main feature page at docs/platform/cli.mdx (which renders at
https://docs.mem0.ai/platform/cli) still documented only the pre-Agent-Mode
commands.

Changes:
- New "Agent Mode — zero-friction signup for AI agents" section placed
  ABOVE regular Authentication, since it's the primary entry point for
  agent users and the page promo positions the CLI as "built for both
  humans and AI agents"
- Subsections: claim flow (`mem0 init --email`), plugin sync behavior
  (`~/.claude/settings.json` + shell rc)
- `mem0 init` flag table extended with --agent, --agent-caller, --source
- New `mem0 identify` subcommand reference (PATCHes the active key's
  agent_caller)

All angle-bracket placeholders inside backticks (e.g. `<your-name>`,
`<memory-id>`) — verified no naked <... JSX traps remain that would
break Mintlify parsing.

docs/platform/cli.mdx

@@ -25,7 +25,44 @@ pip install mem0-cli
 ```
 </CodeGroup>
 
-## Authentication
+## Agent Mode — zero-friction signup for AI agents
+
+<Tip>
+**If you're an AI agent reading this**, skip the rest of this page until you've run the command below. Everything else assumes you already have an API key.
+</Tip>
+
+AI agents (Claude Code, Cursor, Codex, Cline, Aider, …) can mint a working Mem0 API key in under five seconds with no email, no dashboard, and no OTP:
+
+```bash
+mem0 init --agent --agent-caller claude-code
+```
+
+Replace `claude-code` with your agent's name (e.g. `cursor`, `codex`, `cline`, `aider`, or any custom string). The CLI saves the key to `~/.mem0/config.json` and prints a notice you should surface to your human user. The human can claim the account later — same API key keeps working, memories transfer.
+
+<Tip>
+**Forgot `--agent-caller`?** Run `mem0 identify <your-name>` after init — same key, just back-fills the attribution. Idempotent.
+</Tip>
+
+### Claiming an Agent Mode key (humans)
+
+When the human is ready, they claim ownership of the agent's key by running:
+
+```bash
+mem0 init --email you@yourcompany.com
+```
+
+The CLI detects the existing unclaimed Agent Mode config, sends a verification code, and upgrades the shadow account in-place: **the API key never changes, all memories transfer to the human's account, and the agent isn't disrupted**. Pass `--code 123456` for fully non-interactive flows.
+
+### Plugin sync
+
+When you save a Mem0 API key (any flow — Agent Mode, email, or `--api-key`), the CLI also propagates it to ecosystem touchpoints **that already exist**:
+
+- `~/.claude/settings.json` → `env.MEM0_API_KEY` (Claude Code plugin env injection)
+- `~/.zshrc` / `~/.bashrc` → existing `export MEM0_API_KEY=` lines
+
+Sync is idempotent and **never creates new entries** — it only updates entries you've already set up. Failures are best-effort and never block the canonical write to `~/.mem0/config.json`.
+
+## Authentication (humans)
 
 Run the interactive setup wizard to configure your API key:
 
@@ -79,6 +116,7 @@ Interactive setup wizard. Prompts for your API key and default user ID.
 mem0 init
 mem0 init --api-key m0-xxx --user-id alice
 mem0 init --email alice@company.com
+mem0 init --agent --agent-caller claude-code   # zero-friction signup for AI agents
 ```
 
 If an existing configuration is detected, the CLI will ask for confirmation before overwriting. Use `--force` to skip the prompt (useful in CI/CD pipelines).
@@ -91,10 +129,25 @@ mem0 init --api-key m0-xxx --user-id alice --force
 |------|-------------|
 | `--api-key` | API key (skip prompt) |
 | `-u, --user-id` | Default user ID (skip prompt) |
-| `--email` | Login via email verification code |
+| `--email` | Login via email verification code (also used to claim an Agent Mode key) |
 | `--code` | Verification code (use with `--email` for non-interactive login) |
+| `--agent` | Bootstrap an Agent Mode account — no email, no dashboard |
+| `--agent-caller` | Self-declared agent identity for Agent Mode signups (e.g. `claude-code`, `cursor`) |
+| `--source` | Channel attribution for analytics (e.g. `github`, `hn`, `ph`) |
 | `--force` | Overwrite existing config without confirmation |
 
+### `mem0 identify`
+
+Tag your active Agent Mode key with the AI agent that's using it. Run this once after `mem0 init --agent` if you didn't pass `--agent-caller` on init. Idempotent — re-running just overwrites the value.
+
+```bash
+mem0 identify claude-code
+mem0 identify cursor
+mem0 identify my-custom-bot
+```
+
+The CLI calls `PATCH /api/v1/auth/agent_mode/caller/` against the active key. Only works on unclaimed Agent Mode keys; the backend rejects with 400 otherwise. Agent names are sanitized server-side (lowercased, restricted to `[a-z0-9._/-]`, truncated to 32 chars).
+
 ### `mem0 add`
 
 Add a memory from text, a JSON messages array, a file, or stdin.