Overhaul docs retrieval and web search quality

Replace the abandoned llms-txt-mcp/Chroma docs backend with an in-repo
MCP service: SQLite WAL + FTS5 + sentence-transformer embeddings,
transactional source replacement, persisted state across restarts,
singleflight refresh with conditional requests, hybrid lexical/semantic
ranking with exact-duplicate collapse, source/host filters, and
explicit-by-default content retrieval. Add docs_rebuild and a
docs-rebuild CLI command.

Add deterministic llms-full.txt snapshot generation for machine-local
menus with hash-validated provenance manifests; lifecycle commands
promote a local menu to its snapshot only when the manifest validates.
Switch public source profiles to content-bearing llms-full.txt feeds.

Improve web search: bounded provider fallback with per-attempt
diagnostics and cancellation, an optional Brave Search API provider,
strict SearXNG engine selection, capped link/media extraction, and a
real engine=browser renderer that routes every request through the
existing SSRF vetting while blocking WebSockets, non-GET traffic, and
private destinations.

Extend release checks with offline unit suites and isolated candidate
container tests for both images.

docker/docs/tests/test_parser.py

@@ -0,0 +1,101 @@
+from __future__ import annotations
+
+import unittest
+
+from context_docs.parser import parse_llms_text
+
+
+class ParserTest(unittest.TestCase):
+    def test_standard_menu_preserves_target_url_and_retrievable_content(self) -> None:
+        parsed = parse_llms_text(
+            """# Rails Docs
+
+> Curated official documentation.
+
+## Active Record
+
+- [Associations](https://guides.rubyonrails.org/association_basics.html): Model relationships
+""",
+            "http://127.0.0.1:8769/rails/llms.txt",
+        )
+
+        self.assertEqual("standard-menu", parsed.format)
+        self.assertEqual(1, len(parsed.documents))
+        document = parsed.documents[0]
+        self.assertEqual("https://guides.rubyonrails.org/association_basics.html", document.canonical_url)
+        self.assertIn("Model relationships", document.content)
+        self.assertIn("https://guides.rubyonrails.org/association_basics.html", document.content)
+
+    def test_full_bundle_is_not_misclassified_by_interior_yaml_or_rule(self) -> None:
+        parsed = parse_llms_text(
+            """# Build a client
+
+Some content.
+
+---
+title: This is an embedded example
+description: It is not file frontmatter
+---
+
+# Elicitation
+
+URL mode details.
+""",
+            "https://example.test/llms-full.txt",
+        )
+
+        self.assertEqual("markdown-full", parsed.format)
+        self.assertEqual(["Build a client", "Elicitation"], [doc.title for doc in parsed.documents])
+
+    def test_full_bundle_with_bullet_links_keeps_prose_sections(self) -> None:
+        parsed = parse_llms_text(
+            """# Persistence
+
+This substantial section explains durable checkpoint behavior.
+
+- [Related guide](https://example.test/guide): Read more
+
+# Streaming
+
+Streaming emits incremental updates.
+""",
+            "https://example.test/llms-full.txt",
+        )
+
+        self.assertEqual("markdown-full", parsed.format)
+        self.assertEqual(["Persistence", "Streaming"], [doc.title for doc in parsed.documents])
+        self.assertIn("durable checkpoint", parsed.documents[0].content)
+
+    def test_repeated_frontmatter_accepts_optional_description(self) -> None:
+        parsed = parse_llms_text(
+            """---
+title: First
+---
+First body.
+---
+title: Second
+description: Second description
+---
+Second body.
+""",
+            "https://example.test/llms-full.txt",
+        )
+
+        self.assertEqual("yaml-full", parsed.format)
+        self.assertEqual(["First", "Second"], [doc.title for doc in parsed.documents])
+        self.assertEqual("Second description", parsed.documents[1].description)
+
+    def test_long_sections_are_split_without_losing_tail_identifiers(self) -> None:
+        body = "Paragraph.\n\n" * 100 + "IMMICH_IGNORE_MOUNT_CHECK_ERRORS disables mount checks."
+        parsed = parse_llms_text(
+            f"# Environment Variables\n\n{body}",
+            "https://example.test/llms-full.txt",
+            max_chunk_chars=500,
+        )
+
+        self.assertGreater(len(parsed.documents), 1)
+        self.assertTrue(any("IMMICH_IGNORE_MOUNT_CHECK_ERRORS" in doc.content for doc in parsed.documents))
+
+
+if __name__ == "__main__":
+    unittest.main()