Add tunie/docs (full context + open-source roadmap); refresh README

docs/CONTEXT.md captures the entire reverse-engineering effort in one place:
KWP2000 protocol, AES-128 seed/key, the map format (dc decrypt -> flat-ROM
unpack -> directory -> fe table pointers), the fuel/ignition table map, the
validated SAI/O2 device flags, checksums, hardware, and a per-finding confidence
table.

docs/ROADMAP.md covers open-sourcing (legal/IP posture on proprietary maps and
the AES keys, repo hygiene, packaging/CI, community) and the technical path to
tuning the bike (first contact -> ROM dump -> calibration model -> write path ->
editor), with immediate next steps and a risk register.

Top-level README refreshed to describe the whole project (tool + viewer +
research) and point at docs/.

tunie/docs/README.md

@@ -0,0 +1,14 @@
+# tunie docs
+
+- **[CONTEXT.md](CONTEXT.md)** — full technical context: everything reverse-engineered
+  and built (protocol, AES seed/key, map decrypt/unpack, table map, device flags,
+  checksums, validation status & confidence). Read this first.
+- **[ROADMAP.md](ROADMAP.md)** — the plan: getting this open-sourced (legal, hygiene,
+  packaging), the technical path to actually tuning the bike, immediate next steps,
+  and the risk register.
+
+Deeper per-topic writeups live next to the code:
+- `../README.md`, `../STATUS.md` — the read-only tool + project status
+- `../research/FINDINGS.md` — AES-128 seed/key
+- `../viewer/FORMAT.md` — map file format
+- `../research/reference-maps/{README,TABLES,DEVICES}.md` — decrypt, table map, device flags