printer sid BUGFIX include nodes augmented into other modules

[manoe]

printer sid BUGFIX: include nodes augmented into other modules

Summary

The RFC 9595 SID generator does not assign SIDs to data nodes that a module
contributes to other modules via augment. For any module that places its
data by augmenting another module, lys_sid_gen()/lys_sid_update() (and
yanglint -g) produce a .sid file containing only the module item and no
data items. This PR makes the generator collect those augmented-in nodes.

Problem

sid_collect_items() gathered data-namespace items only from the processed
module's own compiled tree:

LY_CHECK_RET((rc = lysc_module_dfs_full(module, collect_data_cb, callback_data)), rc);

Nodes that module augments into another module live in the target module's
compiled tree (their node->module still points back to the augmenting
module), so lysc_module_dfs_full(module, ...) never visits them. As a result
they receive no SID.

Minimal example — a module whose only data is an augment into another module:

module a1 {
  import b1 { prefix b1; }
  augment "/b1:cont" {
    leaf x { type string; }
  }
}

Before this PR, a1's generated .sid contains a single item (module a1) and
0 data items; the augmented-in /b1:cont/a1:x is missing.

Fix

Collect all nodes defined by the processed module, wherever they are grafted
in the compiled schema:

• collect_data_cb() now attributes each node to its defining module and skips
  nodes whose node->module differs from the module being processed. This both
  (a) lets us safely traverse other modules' trees and pick only the
  augmented-in nodes, and (b) fixes a latent mis-attribution where a module's own
  .sid could wrongly include nodes augmented into it by others.
• After walking the module's own tree, sid_collect_items() also walks every
  context module whose augmented_by references the processed module (guarded on
  ->compiled), using the same callback.

libyang already implements augment target modules when the augmenting module is
implemented (lys_precompile_augments_deviations()), so the target trees are
present during generation. The existing choice/case handling and top-level
extension-data (yang-data/structure) traversal are unchanged.

Backward compatibility

Output is unchanged for modules that do not augment other modules. The only
behavioral change is correct attribution: augmented-in nodes now appear in the
augmenting module's .sid, and are no longer (incorrectly) included in the
target module's .sid.

Notes

• Deviation-introduced nodes (deviated_by) are a separate RFC 9595 concern and
  are intentionally out of scope here.

[michalvasko]

Thanks, seems fine. The RFC does not mention explicitly how to process augments but this should be correct.