docs: fix tests/README.md — correct nwnss test paths and add missing sections

NSS helper tests live in tests/nwnss/ with nwnss.* prefix, not in
tests/core/ with nwcore.* prefix as previously documented. Add explicit
sections for tests/nwnss, tests/flaim and tests/fake. Fix the intro
example (nwcore.unicode does not exist; nwnss.unicode does).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/README.md

@@ -4,30 +4,45 @@ The test tree contains small smoke helpers for protocol areas that are easier to
 exercise outside the normal install flow.
 
 CTest names use dotted library/protocol prefixes so the output groups tests by
-owner: `nwcore.ini`, `nwcore.log`, `nwcore.unicode`, `nwtui.smoke`,
-`nwfs.dirquota`, `nwflaim.api.create-query-encrypt`, and so on.  Keep new test
-names in that shape instead of adding flat underscore-style names.
+owner: `nwcore.ini`, `nwcore.log`, `nwtui.smoke`, `nwfs.dirquota`,
+`nwnss.bit`, `nwnss.unicode`, `nwflaim.api.create-query-encrypt`, and so on.
+Keep new test names in that shape instead of adding flat underscore-style names.
 
+## Core library unit tests
 
-## Core and TUI library unit tests
+`tests/core` contains CTest unit tests for Mars-native `libnwcore` facilities:
 
-`tests/core` contains normal CTest unit tests for `libnwcore` facilities.
-Keep them grouped by core subsystem: `tests/core/ini` covers the shared
-`nw_ini_*` reader/writer facade, `tests/core/log` covers the `nwlog_*`
-level-mask facade, and imported NSS low-level helpers are covered by sibling
-subdirectories such as `tests/core/bit`, `tests/core/bitmap`,
-`tests/core/crc`, `tests/core/xctype`, `tests/core/xstring`,
-`tests/core/utf8`, `tests/core/codepage`, `tests/core/utc`,
-`tests/core/guid`, `tests/core/id`, `tests/core/zalloc`, and
-`tests/core/unicode`.  Future Unicode/codepage/byte coverage should keep using
-new focused sibling
-subdirectories instead of being added as a flat list.
+- `tests/core/ini` — `nwcore.ini`: shared `nw_ini_*` reader/writer facade
+- `tests/core/log` — `nwcore.log`: `nwlog_*` level-mask facade
 
 `tests/tui` contains non-interactive `libnwtui` smoke tests.  These tests must
 not require a real terminal or compare full-screen terminal output; test widget
 and style logic outside the termbox2 runtime, and keep true terminal smokes
 optional if they are added later.
 
+## NSS unit tests
+
+`tests/nwnss` contains CTest unit tests for the imported NSS runtime in
+`libnwnss`.  Each subdirectory covers one NSS subsystem and carries the
+`nwnss.` prefix, for example `nwnss.bit`, `nwnss.bitmap`, `nwnss.crc`,
+`nwnss.xctype`, `nwnss.xstring`, `nwnss.utf8`, `nwnss.codepage`, `nwnss.utc`,
+`nwnss.guid`, `nwnss.id`, `nwnss.zalloc`, `nwnss.unicode`, `nwnss.namespace`,
+and many more.  Future NSS imports should add a focused sibling subdirectory
+with a matching `nwnss.<subsystem>` test name.
+
+## FLAIM unit tests
+
+`tests/flaim` contains CTest unit tests for the FLAIM and XFLAIM database
+libraries: `nwflaim.api.create-query-encrypt`, `nwxflaim.api.alloc`, and
+`nwflaimsql.header-link`.  These tests require the `ENABLE_DIRECTORY` build
+option.
+
+## Offline dependency stubs
+
+`tests/fake` contains minimal GDBM and PAM header/library stubs for
+compile-only local builds without system development packages.  See
+`tests/fake/README.md` for usage; do not use these stubs for runtime testing.
+
 ## NWFS lib/CTest coverage
 
 `nwfs.dirquota` runs `tests/nwfs/nwfs_dirquota_test` as a normal CTest/libnwfs plausibility test for