feat: flip swap mechanism on sagitta — MD as primary, RST as override

Mirror of #1899 (current) and #1900 (circinus) for sagitta. Same logic,
same scripts, per-branch file set.

Changes:
- Rename docs/**/md-<stem>.md to docs/**/<stem>.md (drop md- prefix) for
  all 210 stems previously listed in docs/_swap.txt
- Rename docs/**/<stem>.rst to docs/**/rst-<stem>.rst (add rst- prefix)
  for the same 210 stems
- Repurpose docs/_swap.txt as docs/_rst_overrides.txt; initially empty
- conf.py exclude_patterns flipped: rst-*.rst excluded by default
- conf.py runtime-artifact references updated to _rst_override_state.json
  and _md_exclude.txt
- scripts/swap_sources.py imported from current (post-#1899 rewrite, with
  inverted rename direction)
- scripts/import_myst.py and tests/test_import_myst.py deleted (obsolete)
- tests/test_swap_sources.py imported from current (post-#1899 rewrite)

Side-effect: fixes the same 404 on /en/1.4/ View page source links that
#1899 fixed for /en/rolling/ and #1900 fixed for /en/1.5/.

Per-branch differences vs #1899:
- sagitta has 210 stems vs current's 254 (sagitta has no vpp pages and
  fewer current-only features; cli + installation/cloud/aws are still
  RST-only on sagitta pending the title-level fix follow-up)
- otherwise the script/conf.py/test changes are byte-identical with current

Generated by robots https://vyos.io

12 files changed, 0 insertions, 0 deletions

diff --git a/docs/contributing/md-build-vyos.md b/docs/contributing/build-vyos.md
index 4541e828..4541e828 100644
--- a/docs/contributing/md-build-vyos.md
+++ b/docs/contributing/build-vyos.md
diff --git a/docs/contributing/md-debugging.md b/docs/contributing/debugging.md
index 73b622c6..73b622c6 100644
--- a/docs/contributing/md-debugging.md
+++ b/docs/contributing/debugging.md
diff --git a/docs/contributing/md-development.md b/docs/contributing/development.md
index dcfe257a..dcfe257a 100644
--- a/docs/contributing/md-development.md
+++ b/docs/contributing/development.md
diff --git a/docs/contributing/md-issues-features.md b/docs/contributing/issues-features.md
index 6a748f36..6a748f36 100644
--- a/docs/contributing/md-issues-features.md
+++ b/docs/contributing/issues-features.md
diff --git a/docs/contributing/build-vyos.rst b/docs/contributing/rst-build-vyos.rst
index a9dacda4..a9dacda4 100644
--- a/docs/contributing/build-vyos.rst
+++ b/docs/contributing/rst-build-vyos.rst
diff --git a/docs/contributing/debugging.rst b/docs/contributing/rst-debugging.rst
index e03f3f81..e03f3f81 100644
--- a/docs/contributing/debugging.rst
+++ b/docs/contributing/rst-debugging.rst
diff --git a/docs/contributing/development.rst b/docs/contributing/rst-development.rst
index e39af3a5..e39af3a5 100644
--- a/docs/contributing/development.rst
+++ b/docs/contributing/rst-development.rst
diff --git a/docs/contributing/issues-features.rst b/docs/contributing/rst-issues-features.rst
index 9b6602f9..9b6602f9 100644
--- a/docs/contributing/issues-features.rst
+++ b/docs/contributing/rst-issues-features.rst
diff --git a/docs/contributing/testing.rst b/docs/contributing/rst-testing.rst
index 78860c06..78860c06 100644
--- a/docs/contributing/testing.rst
+++ b/docs/contributing/rst-testing.rst
diff --git a/docs/contributing/upstream-packages.rst b/docs/contributing/rst-upstream-packages.rst
index 5c48bbb3..5c48bbb3 100644
--- a/docs/contributing/upstream-packages.rst
+++ b/docs/contributing/rst-upstream-packages.rst
diff --git a/docs/contributing/md-testing.md b/docs/contributing/testing.md
index b2929936..b2929936 100644
--- a/docs/contributing/md-testing.md
+++ b/docs/contributing/testing.md
diff --git a/docs/contributing/md-upstream-packages.md b/docs/contributing/upstream-packages.md
index 6e7a7fb6..6e7a7fb6 100644
--- a/docs/contributing/md-upstream-packages.md
+++ b/docs/contributing/upstream-packages.md