agent: lumotia-rebrand — fix QC blockers for phase 2

Phase 2 QC found three explicit blockers + a broader sweep needed:

Explicit (QC-named):
- crates/mcp/src/lib.rs:15 — SERVER_NAME public MCP wire identity
- crates/transcription/build.rs:59 — panic message prefix
- crates/llm/tests/content_tags_smoke.rs:7 — docstring -p flag

Swept (string literals + dev env vars + doc comments + test fixtures):
- crates/mcp/src/main.rs — eprintln log prefixes
- src-tauri/src/commands/diagnostics.rs — diagnostic filename + MAGNOTIA_VERSION
- src-tauri/src/commands/audio.rs — recording filename pattern lumotia-<secs>-...wav
- src-tauri/src/commands/fs.rs — test placeholder path
- crates/transcription/src/model_manager.rs — .lumotia-verified marker
- crates/storage/src/database.rs — lumotia-storage-ro-<pid> temp dirs + doc comments
- crates/cloud-providers/src/keystore.rs — LUMOTIA_API_KEY_<PROVIDER> env var
- crates/audio/src/{wav,decode}.rs — lumotia_test_* / lumotia_decode_* test fixtures
- crates/core/src/tuning.rs — LUMOTIA_INFERENCE_THREADS env var
- All MAGNOTIA_LLM_TEST_MODEL / MAGNOTIA_WHISPER_TEST_* env vars
- Doc comments referencing crate names

Excluded (intentional Phase 4/5 scope):
- magnotia_preferences, magnotia_history, magnotia_morning_triage_last_shown
  DB setting keys (Phase 5 paths.rs migration)
- magnotia_startup tracing target (Phase 4)
- crates/core/src/paths.rs (Phase 5 wholesale rewrite + migration shim)

cargo build --workspace passes. cargo test --workspace: 330 pass, 0 fail.

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

crates/mcp/src/main.rs

@@ -1,4 +1,4 @@
-//! Stdio entry point for magnotia-mcp. Reads newline-delimited JSON-RPC messages
+//! Stdio entry point for lumotia-mcp. Reads newline-delimited JSON-RPC messages
 //! from stdin, dispatches via `lumotia_mcp::handle_message`, writes responses to
 //! stdout. Logs land on stderr so they don't collide with the JSON-RPC stream.
 
@@ -8,7 +8,7 @@ use tokio::io::{AsyncBufReadExt, AsyncWriteExt, BufReader};
 async fn main() -> anyhow::Result<()> {
     let db_path = lumotia_storage::database_path();
     eprintln!(
-        "[magnotia-mcp] opening Magnotia database at {} (read-only)",
+        "[lumotia-mcp] opening Lumotia database at {} (read-only)",
         db_path.display()
     );
     // Open read-only at the connection level so the MCP server cannot write
@@ -16,7 +16,7 @@ async fn main() -> anyhow::Result<()> {
     // exposes. Migrations are deliberately skipped — this binary never owns
     // the schema; the main app is the single migration writer.
     let pool = lumotia_storage::init_readonly(&db_path).await?;
-    eprintln!("[magnotia-mcp] ready, waiting for JSON-RPC on stdin");
+    eprintln!("[lumotia-mcp] ready, waiting for JSON-RPC on stdin");
 
     let mut lines = BufReader::new(tokio::io::stdin()).lines();
     let mut stdout = tokio::io::stdout();
@@ -38,7 +38,7 @@ async fn main() -> anyhow::Result<()> {
                 // logged and continued, dropping the response —
                 // clients saw silence instead of a structured error
                 // (2026-04-22 review MAJOR).
-                eprintln!("[magnotia-mcp] parse error: {err}");
+                eprintln!("[lumotia-mcp] parse error: {err}");
                 lumotia_mcp::parse_error_response(&err.to_string())
             }
         };