scripts / make: Add Recommends support

The spec generator only supports Requires, Conflicts and Provides from
the [pkg.requires.*], [pkg.conflicts.*] and [pkg.provides.*] sections of
make/project.conf. A package that works without but is better with another
package, like jw-amavis-run without jw-clamav-run, must hard-require it, so
the dependency is pulled in on every install and cannot be removed without
dragging the depending package along.

This commit adds Recommends support to the spec generation chain:

- CmdPkgRecommends: new pkg-recommends command that reads the
  [pkg.recommends.<flavour>] sections, same base as pkg-requires
- pkg-dist.mk: compute PKG_RECOMMENDS_RUN and pass it to pkg.sh via a new
  -E option
- pkg.sh: accept -E and forward it to the mkspec wrapper
- mkspec-wrapper.sh: accept -E and export RECOMMENDS_RUN
- create-mkspec.sh: emit a Recommends: line when RECOMMENDS_<subpkg> is set
- create-mkdebian.sh: emit a Recommends: field in the debian control file

Projects without a [pkg.recommends.*] section generate unchanged specs:
every new line is guarded by a non-empty test. zypper follows Recommends by
default, so existing OpenSUSE installations are unaffected; a recommended
package can be removed without dragging the depending package along.

Assisted-by: unsloth/Qwen3.8-27B-GGUF:Q4_K_M with pi.dev v0.85.1
Signed-off-by: Jan Lindemann <jan@janware.com>

test/integration/jw-pkg/help/test-expected.txt

@@ -246,6 +246,7 @@ Available subcommands of projects:
     pkg-conflicts       Print packages conflicting with a given package
     pkg-provides        Print packages and capabilities provided by a given
                         package
+    pkg-recommends      Print recommended packages
     pkg-requires        Print packages required for a given package
     proj-dir            Print directory of a given package
     pythonpath          Generate PYTHONPATH for given modules
@@ -584,6 +585,58 @@ usage: jw-pkg.py projects pkg-provides [-h] [-S [SUBSECTIONS]]
 
 Print packages and capabilities provided by a given package
 
+positional arguments:
+  flavours              Dependency flavours (run, build, devel, release),
+                        separated by comma or whitespace
+  modules               Modules (default: None)
+
+options:
+  -h, --help            show this help message and exit
+  -S, --subsections [SUBSECTIONS]
+                        Subsections to consider, separated by comma or
+                        whitespace (default: None)
+  -d, --delimiter [DELIMITER]
+                        Output words delimiter (default: , )
+  -p, --no-subpackages  Cut -run and -devel from package names (default:
+                        False)
+  --dont-strip-revision
+                        Always treat VERSION macro as VERSION-REVISION
+                        (default: False)
+  --expand-semver-revision-range
+                        Always treat =VERSION macro as >= VERSION-0 and <
+                        (VERSION+1)-0 (default: False)
+  --syntax {semver,debian,names-only}
+                        Output syntax (default: semver)
+  --recursive           Find dependencies recursively (default: False)
+  --dont-expand-version-macros
+                        Don't expand VERSION and REVISION macros (default:
+                        False)
+  --ignore [IGNORE]     Packages that should be ignored together with their
+                        dependencies (default: )
+  --skip-excluded       Don't consider or output modules matching the os
+                        cascade in their [build].exclude config (default:
+                        False)
+  --hide-self           Don't include projects listed in <modules> in the
+                        output (default: False)
+  --hide-jw-pkg         Don't include packages from requires.jw in the output
+                        (default: False)
+  --quote               Put double quotes around each listed dependency
+                        (default: False)
+============= Running: jw-pkg.py -t ../../../.. --log-level info projects pkg-recommends --help
+usage: jw-pkg.py projects pkg-recommends [-h] [-S [SUBSECTIONS]]
+                                         [-d [DELIMITER]] [-p]
+                                         [--dont-strip-revision]
+                                         [--expand-semver-revision-range]
+                                         [--syntax {semver,debian,names-only}]
+                                         [--recursive]
+                                         [--dont-expand-version-macros]
+                                         [--ignore [IGNORE]] [--skip-excluded]
+                                         [--hide-self] [--hide-jw-pkg]
+                                         [--quote]
+                                         flavours [modules ...]
+
+Print recommended packages
+
 positional arguments:
   flavours              Dependency flavours (run, build, devel, release),
                         separated by comma or whitespace