Fix streamlit deploy failure when pages/*.py overlaps with pages/ directory

[sfc-gh-moczko]

Summary

Fixes #2741.

snow streamlit deploy fails with NotInDeployRootError when both pages/ (directory) and pages/*.py (glob) appear in artifacts and a pages/ directory exists on disk.

Root cause

_ArtifactPathMap.put() walks directory sources to mark children in _dest_is_dir, but does not register those children in __dest_to_src. When a glob like pages/*.py later resolves to the same files, __dest_to_src.get(dest) returns None instead of the existing source, so the duplicate mapping is silently added. During symlink_or_copy(), the second mapping calls Path.resolve() on an already-created symlink, which follows it back to the project source directory — outside the deploy root — and raises NotInDeployRootError.

Fix

_ArtifactPathMap.put() (bundle_map.py) — Two changes in the put() method:

1. Directory walk now registers children in __dest_to_src: Each file discovered during os.walk is recorded as __dest_to_src[child_dest] = child_src. If a different source already maps to that destination, TooManyFilesError is raised immediately.
2. File-to-file branch returns early on same-source duplicates: When current_source == src, the mapping is redundant (already covered by a parent directory walk), so put() returns without adding a duplicate entry.

convert_streamlit_to_v2_data() (definition_conversion.py) — Defense-in-depth:

Adds _is_path_covered_by_directory() helper. During V1→V2 definition conversion, additional_source_files entries like pages/*.py are skipped if they fall under a directory already included as an artifact (e.g. pages/). This prevents the overlapping mappings from reaching _ArtifactPathMap in the first place.

Test plan

• test_bundle_map_deduplicates_directory_and_glob_overlap — directory src/snowpark added first, then explicit src/snowpark/main.py → snowpark/main.py; verifies the duplicate is silently deduplicated and only the directory mapping remains
• test_bundle_map_disallows_different_source_collision_with_directory_child — directory src/snowpark added first, then app/manifest.yml → snowpark/main.py (different source, same dest); verifies TooManyFilesError is raised
• test_bundle_map_disallows_collisions_anywhere_in_deployed_hierarchy — previously @pytest.mark.skip; now passes because directory children are tracked in __dest_to_src
• test_bundle_deduplicates_pages_directory_and_glob — end-to-end StreamlitEntity.bundle() with artifacts: ["streamlit_app.py", "pages/", "pages/*.py"]; verifies the bundle completes and produces the correct output files
• test_v1_to_v2_streamlit_conversion_deduplicates_pages — V1 streamlit with additional_source_files: [pages/*.py] and a pages/ directory on disk; verifies pages/*.py is filtered from the converted V2 artifacts
• test_v1_to_v2_streamlit_conversion_keeps_non_overlapping_additional_files — same setup but with utils/helper.py added; verifies non-overlapping files are preserved while pages/*.py is still filtered
• All 290 existing tests pass with 0 regressions