Add CLI flag surface: -rename/--format/--db/--action/--conflict/-non-strict/-h

Ports FileBot's net.filebot.cli flag surface so Aurora Curator can be scripted,
not just driven through the GUI. Argument parsing and file-expansion are pure
Rust in aurora-curator-core::cli (14 unit tests, no Tauri/network dependency);
orchestration lives in src-tauri/src/cli.rs, which reuses the exact same
binding vocabulary the GUI's RenamePanel.tsx builds client-side and the exact
same TMDB/TVmaze season-caching lookup fetch_metadata already uses, so a
naming scheme renders identically whether it's typed into the app or passed
via --format.

main.rs branches to CLI mode before any Tauri App/window is built at all,
using tauri::async_runtime::block_on to drive the async metadata lookups
(confirmed safe standalone by reading Tauri's own async_runtime.rs) and a
hand-rolled settings::cli_tmdb_token() that replicates Tauri's own
app_config_dir() computation (dirs::config_dir().join(identifier), pinned
against tauri.conf.json by a new test) so a token saved through the GUI's
Fetch Data Settings is found from the CLI path too - the CLI still never
accepts a token as an argument.

Deliberately not ported: --output <dir> (the rename engine's safety
invariant against escaping the source directory tree would need to be
relaxed) and -non-strict is accepted as a no-op (local matching has no
confidence score to loosen).

16 new tests in src-tauri (10 in cli.rs, 1 pinning settings::
APP_CONFIG_IDENTIFIER) plus 14 in aurora-curator-core's cli module - full
workspace suite is 113 passing. README updated with a new "Command-line
usage" section and roadmap item 6 marked done for the CLI surface.

Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01QLbx8ov7zMcdDPEqQm4Y98

src-tauri/Cargo.toml

@@ -19,3 +19,4 @@ serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 walkdir = "2"
 tokio = { version = "1", features = ["sync"] }
+dirs = "6"