feat(mcp): default create_purchase_order to DRAFT status

[dougborg]

Summary

create_purchase_order now creates new POs in DRAFT by default instead of
NOT_RECEIVED. An API-created PO that a human hasn't approved is conceptually an
unsent draft — the operator can review and edit it before committing the order to
the supplier. The previous default forced a manual "send back to draft" fixup in
the Katana UI on every programmatically created PO (5–6 per StockTrim split).

DRAFT support itself already shipped in client v0.50.0 (Apr 9); this PR only
flips the default and clarifies the docs.

Changes

• Flip the status field default None (→ Katana's NOT_RECEIVED) → "DRAFT",
  and send DRAFT explicitly on the apply path rather than leaving it UNSET.
• Preview card reflects DRAFT so the operator sees the target state.
• Expand the status field description, tool docstring, and katana://help
  entry to enumerate DRAFT vs NOT_RECEIVED, how to opt out
  (status="NOT_RECEIVED" for already-placed orders), and how to transition
  later (modify_purchase_order / receive_purchase_order).
• Regression tests: DRAFT default on apply + preview, and explicit
  NOT_RECEIVED still forwards unchanged.

Opt-out

Callers wanting an already-ordered PO pass status="NOT_RECEIVED" explicitly.

Test plan

• uv run poe check — 3783 passed, 8 skipped + 42 browser tests passed
• New regression tests pin DRAFT default (apply + preview) and explicit
  NOT_RECEIVED forwarding
• Verified live MCP inputSchema advertises "default": "DRAFT" with the
  ["DRAFT", "NOT_RECEIVED"] enum end-to-end
• Reviewer: confirm the DRAFT default is the desired cross-cutting behavior
  (affects all PO creation lacking an explicit status — StockTrim split,
  correct_purchase_order, etc.)

Note: requires a katana-erp-dev redeploy to reach the live server.

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR updates the MCP create_purchase_order tool so that newly created purchase orders default to DRAFT (instead of relying on Katana’s API default of NOT_RECEIVED), aligning programmatic PO creation with an “operator-review-first” workflow.

Changes:

• Set CreatePurchaseOrderRequest.status default to "DRAFT" and ensure the apply path sends DRAFT explicitly when unspecified.
• Update preview responses and tool/docs text to reflect the new default and explain how to opt out (status="NOT_RECEIVED").
• Add regression tests covering (a) default-to-DRAFT behavior and (b) explicit NOT_RECEIVED forwarding.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
katana_mcp_server/src/katana_mcp/tools/foundation/purchase_orders.py	Changes the request default, apply-path API payload behavior, preview card status, and expands status documentation.
katana_mcp_server/tests/tools/test_purchase_orders.py	Adds regression tests asserting the new default behavior and explicit override behavior.
katana_mcp_server/src/katana_mcp/resources/help.py	Updates katana://help documentation to reflect DRAFT as the default and clarify semantics.

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated no new comments.