Add phase-by-phase tutorial notes

Add a Tutorial tree that mirrors the roadmap from Phase 0 through Linux bring-up.
Each phase and subphase gets a short learning note with consistent sections for
context, goals, new concepts, mental model, learning tasks, pitfalls, tooling,
testing, and references.

The tutorial material is intentionally explanatory rather than implementation
code. It gives a systems-oriented learner enough FPGA, SystemVerilog, RISC-V,
firmware, and Linux bring-up context to approach each roadmap phase without
turning the notes into copy-paste RTL.

Tutorial/README.md

@@ -0,0 +1,39 @@
+# FPGA-Core Tutorial
+
+This tutorial tree follows `ROADMAP.md`. Each phase and subphase has a learning note
+with the same structure:
+
+- Context
+- Goals
+- New Concepts
+- How To Think About It
+- Learning Tasks
+- Pitfalls
+- Tooling And Testing
+- References
+
+The notes assume strong Linux/systems experience and beginner-to-intermediate FPGA and
+digital-design experience. They intentionally avoid giving implementation code. The goal
+is to explain what to learn, what to verify, and what mistakes to avoid.
+
+## Phase Index
+
+- [Phase 0 - Architecture Contract](phase-00-architecture-contract/phase-00.md)
+- [Phase 1 - ALU + M Unit](phase-01-alu-m-unit/phase-01.md)
+- [Phase 2 - Register File](phase-02-register-file/phase-02.md)
+- [Phase 3 - Decoder](phase-03-decoder/phase-03.md)
+- [Phase 4 - First CPU](phase-04-first-cpu/phase-04.md)
+- [Phase 5 - Branches And Jumps](phase-05-control-flow/phase-05.md)
+- [Phase 6 - Load/Store](phase-06-load-store/phase-06.md)
+- [Phase 7 - Memory-Mapped UART](phase-07-uart-mmio/phase-07.md)
+- [Phase 8 - GCC Toolchain Integration](phase-08-gcc-toolchain/phase-08.md)
+- [Phase 9 - CSRs + M-Mode Traps](phase-09-csrs-traps/phase-09.md)
+- [Phase 10 - Timer](phase-10-timer/phase-10.md)
+- [Phase 11 - Interrupt Controller](phase-11-interrupt-controller/phase-11.md)
+- [Phase 12 - Atomics](phase-12-atomics/phase-12.md)
+- [Phase 13 - Pipeline](phase-13-pipeline/phase-13.md)
+- [Phase 14 - SPI Flash + DRAM](phase-14-flash-dram/phase-14.md)
+- [Phase 15 - M/S/U + Sv32](phase-15-privilege-sv32/phase-15.md)
+- [Phase 16 - Linux Boot Contract](phase-16-linux-boot-contract/phase-16.md)
+- [Phase 17 - Linux](phase-17-linux/phase-17.md)
+