feat(ENG-162): Add tree example

[alnoki]

Changes

Tree

1. Implement red-black tree example with ASM/Rust parity for
   initialize, insert, and remove operations.
2. Add procedural macros for parsing declarative constants.
3. Add tree interface crate with shared constants, bindings, and
   ASM definitions.
4. Add test harness with parity tests covering entrypoint branching,
   input checks, PDA checks, allocation, search, fixup, and
   multi-insert/remove scenarios.
5. Add specs for remove algorithm, insert fixup, rotation
   specialization, tree invariants, test framework, and CU overhead
   analysis.

Housekeeping

1. Update heading layout for memo example.
2. Update examples script to flush test artifacts before runs.
3. Bump sbpf version for CI.
4. Bump opcode index page with new opcodes.

[linear]

ENG-162