feat(standards): add P2idNote bon builder, remove create() factory

[VAIBHAVJINDAL3012]

Closes 0xMiden#2283.

Summary by CodeRabbit

Release Notes

• Breaking Changes

  • Replaced P2idNote::create factory method with a builder-based API (P2idNote::builder()) for more flexible note construction.

• New Features

  • Added fluent builder methods for P2ID notes: .asset(), .attachment(), and .generate_serial_number().
  • Exposed P2ID_SCRIPT_ROOT constant for public access to the P2ID script root hash.

[coderabbitai]

📝 Walkthrough

Walkthrough

This PR refactors P2idNote from a unit struct with a create() factory method into a full struct with concrete fields and a #[bon]-based builder pattern. The new API exposes a SCRIPT_ROOT constant, provides accessor methods and builder extensions (.asset(), .attachment(), .generate_serial_number()), and implements bidirectional conversion traits (From<P2idNote> and TryFrom<&Note>). All dependent test code is migrated to the new builder API.

Changes

P2idNote Builder Refactoring

Layer / File(s)	Summary
P2idNote struct, SCRIPT_ROOT, and builder constructor crates/miden-standards/src/note/p2id.rs	P2idNote transitions from unit placeholder to a concrete struct with sender, storage, serial_number, note_type, assets, and attachments fields. A public SCRIPT_ROOT lazy-locked constant exposes the compiled P2ID script root. The #[bon]-backed new() constructor and public accessor methods (sender(), target(), script(), script_root(), etc.) are introduced.
Builder extension methods and conversion traits crates/miden-standards/src/note/p2id.rs	Builder extension methods .asset(), .attachment(), and .generate_serial_number() enable fluent note construction. From<P2idNote> for Note provides infallible conversion; TryFrom<&Note> for P2idNote reconstructs P2idNote from a protocol note while validating script-root matching.
P2idNote unit tests crates/miden-standards/src/note/p2id.rs	Test module imports expand to include asset and RNG types. New builder-focused test cases validate minimal construction, asset/attachment accumulation, duplicate-faucet rejection, RNG-based serial generation, SCRIPT_ROOT consistency, and round-trip conversions via From/TryFrom.
Public SCRIPT_ROOT re-export crates/miden-standards/src/note/mod.rs	The p2id::SCRIPT_ROOT is re-exported as P2ID_SCRIPT_ROOT to expose the P2ID script root to external crate users.
Changelog documentation CHANGELOG.md	A new v0.16.0 (TBD) entry documents the breaking change: P2idNote::create is replaced by the #[bon] builder with new builder methods and SCRIPT_ROOT static, with conversion via From.
Kernel test migrations crates/miden-testing/src/kernel_tests/block/proposed_block_errors.rs, proven_block_success.rs, crates/miden-testing/src/kernel_tests/tx/test_account_interface.rs, test_output_note.rs, test_tx.rs	Kernel tests replace P2idNote::create(...) calls with P2idNote::builder() chains, explicitly configuring sender/target/note_type/assets, generating serial numbers via builder RNG, and converting results to Note. Imports are adjusted to include Note type.
Mock chain and auth test migrations crates/miden-testing/src/mock_chain/chain_builder.rs, crates/miden-testing/tests/auth/hybrid_multisig.rs, multisig.rs, multisig_smart.rs	MockChainBuilder and auth test modules switch from P2idNote::create() to builder-based construction, iterating over asset slices, explicitly generating serial numbers via RandomCoin, and converting built notes to Note type. Import statements add Note alongside NoteType.
Script test migrations crates/miden-testing/tests/scripts/p2id.rs, send_note.rs	Script tests migrate note construction from P2idNote::create() to fluent builder chains, explicitly adding assets one-by-one, generating serial numbers, and appending attachments before building and converting to Note. Imports replace NoteAttachments with Note.

🎯 3 (Moderate) | ⏱️ ~20 minutes

🐰 A struct once plain, now a builder grand,
With SCRIPT_ROOT shining o'er the land!
From create() calls to chains so bright,
All tests now fluent—what a sight! ✨

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the primary changes: introducing a bon-based builder pattern for P2idNote and removing the create() factory method.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch p2id-note-builder

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@CHANGELOG.md`:
- Line 7: Changelog line shows an extra period in the example chain for the new
P2idNote builder; update the example under P2idNote::builder() so the call chain
uses a single dot before build (i.e., change the `..build()?` typo to a
single-dot `build()?`), ensuring the example with sender(..).target(..).build()?
and conversion via Note::from(_) is valid and copy-paste safe.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: a6367466-1eca-4c2e-b413-1e671a22b63d

📥 Commits

Reviewing files that changed from the base of the PR and between 2ef8056 and 13abc41.

📒 Files selected for processing (14)

• CHANGELOG.md
• crates/miden-standards/src/note/mod.rs
• crates/miden-standards/src/note/p2id.rs
• crates/miden-testing/src/kernel_tests/block/proposed_block_errors.rs
• crates/miden-testing/src/kernel_tests/block/proven_block_success.rs
• crates/miden-testing/src/kernel_tests/tx/test_account_interface.rs
• crates/miden-testing/src/kernel_tests/tx/test_output_note.rs
• crates/miden-testing/src/kernel_tests/tx/test_tx.rs
• crates/miden-testing/src/mock_chain/chain_builder.rs
• crates/miden-testing/tests/auth/hybrid_multisig.rs
• crates/miden-testing/tests/auth/multisig.rs
• crates/miden-testing/tests/auth/multisig_smart.rs
• crates/miden-testing/tests/scripts/p2id.rs
• crates/miden-testing/tests/scripts/send_note.rs

[coderabbitai]

⚠️ Potential issue | 🟡 Minor | ⚡ Quick win

Fix invalid builder-chain example in changelog.

Line 7 shows ...target(..)..build()?, which has an extra . and presents an invalid call chain. Please change it to ...target(..).build()? so migration instructions are copy-paste safe.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@CHANGELOG.md` at line 7, Changelog line shows an extra period in the example
chain for the new P2idNote builder; update the example under P2idNote::builder()
so the call chain uses a single dot before build (i.e., change the `..build()?`
typo to a single-dot `build()?`), ensuring the example with
sender(..).target(..).build()? and conversion via Note::from(_) is valid and
copy-paste safe.