fix(api): resolve note directories case-insensitively

[phernandez]

Summary

MCP write_note with directory: "schemas" beside an existing Schemas/ folder silently created a case-duplicate sibling folder instead of resolving to the existing one, and move_note's destination parent had the same failure mode. The failure is an LLM guessing plausible-but-wrong casing; it shows up on Basic Memory Cloud where the storage backend is case-sensitive (local macOS masks it).

The requested directory now resolves against the project's known folders derived from the database (EntityRepository.get_distinct_directories, the same source list_directory uses) — never by probing the filesystem — so local and cloud runtimes resolve identically.

Resolution rules

Applied per path segment, each segment resolving against children of the already-resolved parent (so schemas/drafts matches an existing Schemas/Drafts):

1. Exact match always wins — no behavior change.
2. Unique case-insensitive match — the note lands in the existing folder's casing.
3. Zero matches — the folder is created as given (today's behavior).
4. Multiple case-variant folders already exist (e.g. both Schemas/ and schemas/) — ambiguous; today's exact behavior is kept.

Where it lives

• resolve_directory_casing() in src/basic_memory/utils.py — the pure segment-wise resolver.
• resolve_accepted_note_directory() / resolve_accepted_note_schema_directory() in src/basic_memory/indexing/accepted_note_mutation_runner.py — wired into the accepted-note create (POST), replace (PUT), and move runners, the server-side layer both the local and cloud runtimes share. The PUT path matters because write_note falls back to update on conflict; without it a case-variant directory would rename the existing note into the wrong-cased folder.
• AcceptedNoteMutationEntityRepository protocol gains get_distinct_directories (the concrete EntityRepository already implements it).
• move_note MCP tool: the outcome-validation backstop (move_note falsely reports success for unsupported cross-workspace/cross-project moves #881) now treats a case-only difference between requested and actual landing path as success — that difference is this resolution at work, not a cross-boundary degradation; the success message already reports the actual path.

Out of scope by design: directory moves / case-only folder renames and index dedup of existing duplicates (#1281).

Tests

• tests/utils/test_resolve_directory_casing.py — all four rules, nested segments, ambiguous-parent non-splicing, root/empty inputs (10 tests).
• tests/indexing/test_accepted_note_mutation_runner.py — create resolves (and leaves the route-owned schema untouched), create keeps ambiguous casing, update replaces in place instead of renaming, move resolves the destination parent, move onto a case-variant of the note's own path rejects as same-path (5 tests).
• tests/api/v2/test_knowledge_router.py — real-stack create resolution, nested resolution, ambiguous-siblings passthrough, move resolution (4 tests).
• tests/mcp/test_tool_write_note.py / test_tool_move_note.py — end-to-end write_note and move_note flows land in the existing folder's casing (2 tests).

Verification

uv run pytest tests/utils/test_resolve_directory_casing.py tests/indexing/test_accepted_note_mutation_runner.py   # 46 passed
uv run pytest tests/api/v2/ tests/indexing/ tests/utils/ tests/cloud/test_cloud_services.py tests/index/test_local_accepted_note_repositories.py   # 952 passed, 1 skipped
uv run pytest tests/mcp/test_tool_write_note.py tests/mcp/test_tool_move_note.py   # 103 passed
uv run pytest test-int/mcp/test_write_note_integration.py test-int/mcp/test_move_note_integration.py   # 56 passed
uv run ruff check --fix && uv run ruff format .
uv run ty check src tests test-int   # only pre-existing pymilvus env diagnostics, also present on main

Fixes #1326

🤖 Generated with Claude Code

https://claude.ai/code/session_01G4rbaeHJN3L7CREp5v38J9

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