Several structure fields (now) computed in ocda do not yet have a
consumer outside the `.ssp` writer (which shares ocda fields in a
PEG parsable .ssp file). Their addition is to facilitate future
output processing: each representing document structure
information that document output generators of various formats,
such as html, epub, latex, sql and any DOM based / tree-graph
(node based hierarchical) representations, previously had to, or
would have to, work out for themselves based on what ocda offered
(without them).

Computing them (upstream) in ocda once and sharing them (and
providing the .ssp), means that:

- future output formats can start from prepared structure rather
  than deriving it;

- existing generators can be simplified to consume them instead
  of re-deriving;

- a (dlang) generator could in principle be populated either from
  ocda directly or from a `.ssp` file;

- `.ssp` being PEG parsable puts the same prepared structure in
  reach of implementations in other languages.

`test/test-abstraction-ssp.sh` the `.ssp` reference regression
test is used to catch regression in ocda including these as yet
unused fields, which otherwise would remain unseen until used by
other output-format consumers. This also is the reason issues now
made easily visible and are being addressed (without issue to
existing output generators).

(assisted by Claude-Code)

- dmd 2.112.1
- ldc 1.43.0 beta1
- dub 1.41.0
- dtools 2.112.1

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)

(also cgi_sqlite_search_form.d did not belong here)

(usually integrated as part of a pushed commit)