ocda public surface + dub.json import-path and dyaml cleanupsHEADmain

Three small follow-ups to the ocda/outputs split:

1. Add src/sisudoc/ocda/package.d (module sisudoc.ocda) as a 2-line
   public re-export of sisudoc.ocda.abstraction. Provides downstream
   consumers with a canonical "import sisudoc.ocda;" entry point and
   a stable handle for eventual peer-repo packaging of the
   abstraction library.

2. Fix the D import-path root in dub.json so it matches the declared
   module names:
   - spine:abstraction sub-package
     "importPaths": [ "./src/sisudoc" ] -> [ "./src" ]
   - main package buildTypes (dmd, ldc2, ldmd2, gdc, gdmd)
     "-I=src/sisudoc" -> "-I=src"
   The modules are named sisudoc.ocda.* / sisudoc.outputs.* /
   sisudoc.* so the filesystem-based resolver needs to see
   ./src as the root (so <root>/sisudoc/ocda/X.d resolves).

3. Replace dyaml sub-package's destructive preGenerateCommands
   ("rm -rf ./src/ext_depends/D-YAML/{examples,testsuite}") with
   declarative excludedSourceFiles globs. The two directories do
   not exist in the vendored D-YAML tree, so the rm was a no-op
   in practice; the glob form is defensive (would silently skip
   them if they were ever re-introduced) and removes the
   destructive side-effect from every build.

(assisted by Claude-Code)

1 files changed, 3 insertions, 3 deletions

diff --git a/flake.lock b/flake.lock
index 8ba83bd..1c785f9 100644
--- a/flake.lock
+++ b/flake.lock
@@ -2,11 +2,11 @@
   "nodes": {
     "nixpkgs": {
       "locked": {
-        "lastModified": 1779536132,
-        "narHash": "sha256-q+fF42iv/geEbHfgSzy3tS0FF/EyD6XTZ98E6yxiBO8=",
+        "lastModified": 1779593580,
+        "narHash": "sha256-le3WvQyzAQjBZnb7q2c8C5Fk2c9LgN/Oq+b0KiD4fM4=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "3d8f0f3f72a6cd4d93d0ad13203f2ea1cb7e1456",
+        "rev": "d849bb215dcdf71bce3e686839ccdb4219e84b2f",
         "type": "github"
       },
       "original": {