re-org docs

docs/testing.md

@@ -27,7 +27,7 @@ boot log, memory summary, exception reports — appears on serial as plain text.
 
 QEMU captures that with `-serial file:serial.log`, giving a machine-readable
 transcript. Serial is per-architecture (x86 uses port I/O; an ARM board uses a
-memory-mapped UART), so it lives behind the [architecture](os-development-guide/architecture.md) boundary — and adding
+memory-mapped UART), so it lives behind the [architecture](os-development/architecture.md) boundary — and adding
 a new architecture's UART is what makes the same tests run there.
 
 The serial log sink is **compiled in only under `-Dserial`** (off by default).
@@ -88,7 +88,7 @@ table in `test/qemu_test.py`):
 | `fault-recovery` | a ring-3 process that faults is killed and reaped while init keeps heartbeating — the OS survives | `DANOS-TEST-RESULT: PASS` |
 
 The faulting cases don't print a result line — they deliberately raise a CPU
-exception, and the harness asserts on the [exception report](os-development-guide/interrupts.md) the
+exception, and the harness asserts on the [exception report](os-development/interrupts.md) the
 handler prints (which also reaches serial). This reuses the real fault path as the
 test oracle: if the IDT/TSS weren't wired up, `fault-df` would triple-fault and the
 marker would never appear.