feat: tag claude-code harness on signup + plugin-setup prompt

[dimavrem22]

Tags this harness on self-signup and gives the in-session agent a heads-up about setting up the plugin.

Changes

• setup_wizard.py: pass harness="claude-code" to Inkbox.signup(...) so the backend records which harness self-signed-up.
• prompts.py: add a short CHANNEL_PROMPT note telling the agent to ask the human for permission before configuring this plugin, since it wires native messaging channels into the runtime.

Dependency

Depends on the Inkbox SDK gaining the optional harness parameter on signup(...) (coordinated PR). Passing it is forward-compatible.

Related PRs (agent-signup harness)

• feat: add harness param to agent signup (SDK + CLI + skill) inkbox#79 — SDK (py/ts) + CLI + self-signup skill (adds the harness param this builds on)
• feat: tag claude-code harness on signup + plugin-setup prompt #17
• feat: tag codex harness on signup + plugin-setup prompt codex-plugin#5
• feat: tag openclaw harness on signup + plugin-setup skill openclaw-plugin#20
• feat: tag hermes harness on signup + plugin-setup skill hermes-agent-plugin#19

[dimavrem22]

codex: This now passes harness="claude-code" into Inkbox.signup, but the plugin still declares/installs inkbox>=0.4.7, and _ensure_inkbox_sdk() returns immediately when any older SDK imports successfully. Since the harness keyword is introduced by the SDK PR (0.4.9), existing environments with inkbox==0.4.7 can raise TypeError before the request reaches the server. Please bump the dependency/bootstrap minimum to the SDK version that supports harness, or feature-detect the signup signature and fall back cleanly.

[dimavrem22]

Fixed in f5178f9: bumped inkbox>=0.4.7 → >=0.4.9 (pyproject, INKBOX_REQUIREMENTS, doctor/gateway hints, and the requirement-string test) and added a min-version guard in _ensure_inkbox_sdk() — an importable-but-stale (<0.4.9) SDK is now treated as unsatisfied and upgraded via the existing pip path before the harness= signup call, so the TypeError path is closed.

[dimavrem22]

Correction to my earlier note: the harness-capable SDK release is 0.4.10, not 0.4.9 (0.4.9 is the Rust SDK release). Pins, INKBOX_REQUIREMENTS, the _ensure_inkbox_sdk() min-version guard, doctor/gateway hints, and the requirement-string tests are now all 0.4.10 (c860b25).