* refactor: convert note scripts from program to library format

This change implements issue 0xMiden#2339 - converting note scripts from program
format to library format with @note_script annotation support.

Changes:
- Add @note_script annotation to all standard note scripts (p2id, p2ide,
  swap, mint, burn) in asm/standards/notes/
- Add NoteScript::from_library constructor that finds the procedure with
  @note_script attribute (or falls back to 'main' procedure) and uses it
  as the entrypoint
- Update build.rs to compile note scripts as libraries (.masl) instead of
  programs (.masb) using assemble_library_from_dir with unique namespace
- Update well_known_note.rs to load NoteScript from Library
- Remove wrapper script files (asm/note_scripts/*.masm) that are no longer
  needed
- Add NoteError variants for missing/multiple @note_script procedures

Note: The @note_script attribute propagation from MASM to Library is not
yet fully supported in miden-assembly 0.20. The implementation falls back
to finding a procedure named 'main' when the attribute is not found.

* refactor: use pub use re-exports in note script wrappers

Address review feedback: instead of the temp directory workaround in
build.rs, use simple wrapper files in note_scripts/ that re-export
the main procedure from miden::standards::notes with pub use.

Changes:
- Add wrapper files (BURN.masm, P2ID.masm, P2IDE.masm, MINT.masm,
  SWAP.masm) with pub use re-exports
- Simplify compile_note_scripts in build.rs to use assemble_library
  directly without temp directory hack
- Remove unused ASM_STANDARDS_NOTES_DIR constant and AsmPath import

* refactor: address review feedback for note script library conversion

Changes based on PR review:
- Replace hardcoded note script roots with procref in bridge_out.masm
  and agglayer_faucet.masm (BURN_NOTE_ROOT and P2ID_SCRIPT_ROOT)
- Remove main procedure fallback in NoteScript::from_library, require
  @note_script attribute
- Update note script wrappers to use @note_script attribute with exec
  instead of pub use re-exports (MASM doesn't support attributes on
  pub use)
- Improve error handling in build.rs (replace expect with proper errors)
- Use lowercase library paths (miden::standards::note_scripts::burn)
- Update miden-* dependencies to v0.20.3 for attribute serialization fix

* refactor: remove individual note script libraries

This removes the individual note script wrapper files (BURN, P2ID, P2IDE,
MINT, SWAP) and their separate compilation, as suggested in PR 0xMiden#2340.

Instead of compiling and loading each note script as a separate .masl file,
the note scripts are now loaded directly from the main standards library
using the new NoteScript::from_library_with_path method.

Changes:
- Add NoteScript::from_library_with_path method to extract a specific
  note script procedure from a library containing multiple note scripts
- Remove asm/note_scripts/ wrapper files
- Remove compile_note_scripts function from build.rs
- Update note Rust files (burn.rs, p2id.rs, p2ide.rs, mint.rs, swap.rs)
  to use StandardsLib with procedure path lookup
- Add NoteScriptProcedureNotFound and NoteScriptProcedureMissingAttribute
  error variants

* refactor: use minimal MastForest with external node in from_library_with_path

Instead of copying the entire library's MastForest, create a minimal
forest containing only a single ExternalNode referencing the procedure's
digest. This significantly reduces memory usage as the actual procedure
code will be resolved at runtime via MastForestStore.

* refactor: rename from_library_with_path to from_library_reference

- Renamed NoteScript::from_library_with_path to from_library_reference
  to better indicate that the resulting note script contains only a
  reference to the procedure
- Updated docstring for create_external_node_forest helper function
- Updated all usages in miden-standards note modules

* fix: remove duplicate changelog entry

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Co-authored-by: Philipp Gackstatter <PhilippGackstatter@users.noreply.github.com>