agent: lumotia-rebrand — fix Codex cross-model review blockers

Codex independent review found 11 blockers post-cascade. All addressed.

CRITICAL (data-loss / crash):

10. crates/core/src/paths.rs — migrate_legacy_data_dir_inner used
    fs::rename which fails with EXDEV when source + target are on
    different filesystems (encrypted-home, bind mounts, separate
    $XDG_DATA_HOME partition). Combined with the Phase 5 QC fix that
    made migration errors fatal, this would crash on first launch
    for any user whose data dir spans filesystems. Added
    rename_or_copy_tree() that falls back to copy_dir_recursive +
    remove_dir_all on CrossesDevices / errno 18 (EXDEV). Symlinks
    preserved verbatim. Same fallback applied to magnotia.db ->
    lumotia.db inside the dir.

11. Added 4 unit tests: copy_dir_recursive preserves nested
    structure, rename_or_copy_tree same-filesystem happy path,
    is_cross_device classifies CrossesDevices kind + raw errno 18.

Doc residuals (blockers 1-9):

1. crates/cloud-providers/Cargo.toml — "Wyrdnote pending rebrand"
   description.
2. crates/cloud-providers/src/provider.rs — module docs + test
   fixture Wyrdnote refs.
3. crates/transcription/src/orchestrator.rs — module docs + test
   fixture Wyrdnote refs.
4. docs/roadmap/2026-05-10-pkm-phase-tooling-shortlist.md — phase
   name + outputs/wyrdnote path refs.
5. docs/architecture-map/04-llm-formatting-mcp/llm-tests.md —
   MAGNOTIA_LLM_TEST_MODEL env var.
6. .../cloud-providers-stubs.md — MAGNOTIA_API_KEY_*.
7. docs/architecture-map/03-audio-transcription/tests-and-fixtures.md
   — MAGNOTIA_WHISPER_*.
8. docs/gpu-tuning/plan.md — MAGNOTIA_BENCH_RUN.
9. docs/superpowers/specs/2026-05-09-battery-gpu-aware-thread-tuning-
   design.md + corresponding plan — MAGNOTIA_POWER_STATE_OVERRIDE,
   MAGNOTIA_INFERENCE_THREADS.

cargo test --workspace: 343 pass / 0 fail (up from 339; +4 EXDEV
fallback tests).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/architecture-map/04-llm-formatting-mcp/llm-tests.md

@@ -9,7 +9,7 @@ last_verified: 2026/05/09
 
 > **Where you are:** [Architecture map](../README.md) → [LLM, Formatting, MCP](README.md) → Tests
 
-**Plain English summary.** Two integration smoke tests live under `crates/llm/tests/`. Both gate on the `MAGNOTIA_LLM_TEST_MODEL` environment variable and skip silently when it is not set. They exist to verify that real model loading and inference works end-to-end, but never run in default `cargo test` runs because model load is heavy.
+**Plain English summary.** Two integration smoke tests live under `crates/llm/tests/`. Both gate on the `LUMOTIA_LLM_TEST_MODEL` environment variable and skip silently when it is not set. They exist to verify that real model loading and inference works end-to-end, but never run in default `cargo test` runs because model load is heavy.
 
 ## At a glance
 
@@ -44,7 +44,7 @@ Verifies the Phase 9 `extract_content_tags` surface against a real loaded model.
 
 Path-and-line summary:
 
-- Env-var gate at `crates/llm/tests/content_tags_smoke.rs:17-23`. Same `MAGNOTIA_LLM_TEST_MODEL` as `smoke.rs`.
+- Env-var gate at `crates/llm/tests/content_tags_smoke.rs:17-23`. Same `LUMOTIA_LLM_TEST_MODEL` as `smoke.rs`.
 - Loads the 2B tier (the smoke tests deliberately use the smallest tier so they run quickly even on modest hardware).
 - Realistic transcript: a multi-sentence dictation about a grant application and a meeting.
 - Calls `engine.extract_content_tags(transcript)` and asserts:
@@ -57,7 +57,7 @@ The character-class assertion mirrors `CONTENT_TAGS_GRAMMAR`'s `topic-char ::= [
 ### Run command (from both files' header comments)
 
 ```bash
-MAGNOTIA_LLM_TEST_MODEL=/path/to/model.gguf cargo test -p lumotia-llm \
+LUMOTIA_LLM_TEST_MODEL=/path/to/model.gguf cargo test -p lumotia-llm \
     --test content_tags_smoke -- --nocapture
 ```
 
@@ -84,7 +84,7 @@ Default `cargo test -p lumotia-llm` runs the unit tests (no model load) plus ski
 ## Data flow (for the smoke tests)
 
 ```
-env MAGNOTIA_LLM_TEST_MODEL
+env LUMOTIA_LLM_TEST_MODEL
   → if unset: print message, return (no failure)
   → else: PathBuf
        → LlmEngine::new()
@@ -99,7 +99,7 @@ env MAGNOTIA_LLM_TEST_MODEL
 - **Smoke tests need a 2B model file.** The 2B Q4_K_M GGUF is ~1.28 GB; downloading it once is a manual prerequisite. CI is not currently configured to fetch it.
 - **Smoke tests load the 2B tier specifically.** The smoke test was written against the smallest tier so it runs in a few seconds on a modest machine. Running on the 27B tier through this path would take minutes per test and would saturate VRAM.
 - **No content_tags smoke for the empty-transcript error path.** The test only exercises the happy path. The error path is covered by `extract_content_tags`'s logic and would only surface here if a regression broke the typed deserialise.
-- **`MAGNOTIA_LLM_TEST_MODEL` is the only env-gate.** No second gate for "I have a Vulkan-capable GPU available". `use_gpu: true` is hard-coded; on a CPU-only machine the test will still pass but run slower and produce a llama.cpp warning.
+- **`LUMOTIA_LLM_TEST_MODEL` is the only env-gate.** No second gate for "I have a Vulkan-capable GPU available". `use_gpu: true` is hard-coded; on a CPU-only machine the test will still pass but run slower and produce a llama.cpp warning.
 
 ## See also